Air Combat (Long War)

Overview

UFOs are tougher, faster, and much deadlier in Long War. Along with that, your crafts and armaments are significantly less potent, at least at first. You will need to cycle your craft regularly like your soldiers. UFO kills will grant experience to your pilots and provide a bonus to accuracy. Your pilots will learn UFO flight patterns and weaknesses, therefore they will become much better at shooting down alien craft: sortie experience provides +3% to hit per kill (up to + 30%) and +1% damage per kill (with no top limit). Also, you will find that both your craft and UFOs may sometimes get 'critical hits', with UFOs being downed in a few hits, or your undamaged Interceptor immediately going into near-full red damage indicator.

At the start of the game your fresh pilots are equipped with Avalanche Missiles, which now have an abysmal 40% accuracy. While it is still possible to down the first Scout with one Interceptor, this is an incredibly unlikely event. It's more probable that it would take two, or even three interceptions to bring down even the most basic alien craft.

Players should exert caution and pick and choose their air battles carefully. You will not be able to bring down every single enemy UFO. Sometimes attempting high risk interceptions against tough targets would be detrimental to your campaign due to the highly unpredictable nature of the engagements at the start of the game. Your early game goal should be to get experience for some of your pilots and advance your air-warfare technology in order to keep aliens at bay on the battleground for the Earth's skies. In case you overreach too early, you might quickly find yourself crippled with long repair times and unable to stop alien operations.

There are Research and Engineering projects that will assist in aerial sorties. There are multiple foundry projects to improve your interceptors. There are also three consumables that remain from Vanilla.

As you progress, each type of UFO's statistics also increase, from general 'health' to firing rates, as to keep you on your toes; so don't expect to ever truly dominate the skies. Plus with the added variables to air-interception, there is no clear-cut "UFO X can be brought down by Interceptor Y" table. As such, the Long War's UFO page will be your general guide for how--- or if-- to attempt to engage these potent UFOs.

If the aliens send a UFO and it is damaged, destroyed or lost, the aliens will pay resources for it, limiting their options in the next month.

Damaging UFOs

It is not necessary to shoot down enemy UFOs in order to prevent them from completing their mission. Doing damage to them is sometimes enough to spoil their plans or reduce their effectiveness. The damage that UFO sustains is stored between interceptions, therefore multiple interception attempts is a good idea to limit the damage to your own Air Force. When a player does more than 50% damage to a UFO, you will start seeing explosion effects around it.

Some UFOs will wander about a country's airspace before zooming off. For these, it is sufficient to get the yellow effect described above. Those effects signify that UFO sustained enough damage to prevent it from completing its mission, such as an Anti-Satellite hunt. Note however that you still have a chance to prevent the UFO's mission while doing less than 50% damage, which is simply linear (i.e., the UFO abort mission chance is 0% at full health, 100% at 50% health, and in 2x% general at (100-x)% health). Otherwise, when they leave detectable airspace (whether you have a satellite over the target country or not), there will be a notification of the damage they did in the minor notices that play alongside the Hologlobe during in-game time progression.

Other UFOs will have a set flight path, and a narrow window of opportunity to intercept: to disrupt these missions entirely, these need to be shot out of the sky. Cases like this include Assault Carriers and Abductors.

Long War mod brings back a mechanic from previous generations of XCOM: UFOs can now have full DOA crashes (with minimal Alloy recovery, and no corpses or other artifacts), so in some cases you may want to pull your punches. To compensate, the Council will give cash rewards for UFOs obliterated in flight. The harder hitting weapons have a greater chance of reducing UFOs to a pile of smelted alloys: specifically, it is the strength of the killshot that determines the UFO's survival.

According to johnnylump on the Nexus Forums,

• When a UFO lands it is either conducting a harvest mission (gain resources) or a research mission (gain research). Research missions happen only in countries with satellites -- this is an alien recon-in-force that's a direct attempt to engage XCOM.

• Harvest missions try to avoid countries with satellites, with a greater chance when alien aggro is high, but they pay a resource penalty when they do (representing a second-best, safer option.)

• Damage to UFOs, or losses on the ground, have no bearing on research points or resources gained from the mission ... if the UFO survives, it gets full value.

• Damage to UFOs in the air does deduct resources as a repair cost, which is calculated separately from harvest gains.

Interceptor Weapons and Stances

Air-to-air weapons now have three main damage statistics - Damage, Rate of Fire, and Armor Penetration. UFOs have different armor levels, which reduces the damage done by a weapon if its armor penetration isn't high enough. For example, you start with a choice between Avalanche missiles (medium damage, low armor penetration) and Stingray missiles (low damage, medium armor penetration). Avalanches will be better against unarmored and very lightly armored UFOs, while Stingrays will be better against more armored UFOs.

When launching you can set a combat stance for your interceptors as they launch on a mission:

• Aggressive gives +15% to hit for both you and the UFO. You may not use the dodge consumable when aggressive.
• Balanced plays out like normal.
• Defensive gives -15% to hit for both you and the UFO. You may not use the auto-hit consumable when defensive.

Mathematically and not accounting for interception time, this means that Aggressive is the most efficient stance when your Interceptor aim is lower than UFO aim, while Defensive is strongest when your Interceptor aim is higher than UFO aim. These effects are stronger the bigger the difference. However, Interception time is an issue as UFOs will just leave after some time. Obviously, Aggressive is the most time-effective stance.

UFO Flight Patterns

UFOs can fly at three altitudes: "High", "Low" and "NOE" ("Nap of the Earth,"). The altitude is a clue of what mission the UFO is going on - UFOs flying at NOE altitude are most likely to land, are performing bombing runs, or will generate an Abduction or Terror mission immediately upon arriving at their destination. UFOs at high altitude are hunting satellites. UFOs at low altitude are scouting out your satellites, so they must be dealt with.

UFOs flashing purple on the radar screen are taking aggressive actions: they are either attacking your satellite or bombing civilians. Use the purple flash to differentiate between a landing and a bombing run. If a UFO is NoE but not flashing purple, you can probably let it land and assault it on the ground (though it may also generate another mission type like Abduction or Terror mission).

Strategy

Interception Tactics

• You can have more than six interceptors when you defend one continent. Store your spare interceptors on other continents and make them rotate.
  • Transit time puts repair times on pause, making the damaged interceptor take a few extra days to repair, but transferring in a new Interceptor from another continent will almost always be far quicker than the days it'll take to wait on repairs.
• Always be prepared to cancel an interception if the engagement is not going well for you. Losing an aircraft with an expensive weapons can be devastating to your resources.
• Mashing the Escape key instantly after aborting, and then quickly re-selecting mission control and the UFO will allow you to send a new interceptor out without having to wait for the first one to fly back to base. This can give you marginally more time to down the UFO before it escapes.
  • If the interceptor you aborted with wasn't damaged, you can even send the same interceptor back mid-air and instantly re-engage, without having to fly back & forth and refuel. If you hit first and aren't damaged, consider aborting the interception and instantly re-engaging with the same interceptor.
• If your interceptor fleet is barely holding on, consider aborting when a UFO on a Scout (flying Low) or Hunt mission (flashing purple on the map and flying at High altitude) displays continuous explosion effects, as if it is being hit repeatedly by attacks. This means the UFO has accumulated over 50% damage, which guarantees the failure of their Scout or Hunt mission. You won't get any rewards, but you won't accrue any additional repair times.
  • UFOs tend to flee into orbit when at 50% of HP or less, robbing you of the opportunity to shoot them down for supplies. Try to keep the pressure up.
• Have an idea of how many interceptions are possible before UFO completes its mission or attempts to escape. For example Scouts usually can only be engaged twice with Ravens.
  • Your choice of starting continent and country is also key, as your starting country determines your starting base location; for instance, USA is centrally located in the moderately-sized North America continent, frequently allowing up to 3 interceptions with Scouts in any of the three countries.
  • Meanwhile, Russia is massive and thus difficult to cover as a starting country without losing a few UFOs. Similarly, Australia as a starting country has difficulty intercepting UFOs in other Asia countries due to the long distance between them.
• Use modules in tough situations when you need an extra boost to get the job done. Dodge Module can be used on Defensive and Balanced tactics, Aim Module can be used on Balanced and Aggressive tactics, and Boost module can be used on any stance. The modules are much more worthwhile-- nearly essential-- in Long War. As they do take time to build, it pays to maintain a stock of them.
  • The Aim module is fairly cheap, and is useful throughout a campaign. Keep a large stock of Floater corpses to make these. While an aggressive stance means that all shots have more accuracy, using an Aim module early in a Balanced stance dogfight means drawing first blood while being a little harder to be hit yourself.
  • The Boost module can be used in any stance, and only extends time (as all air-to-air weapons now are counted as 'long range', approach reduction time no longer is affected). More useful in early game, when you need more time to do enough damage with the weaker weapons and less experienced pilots.
  • The Dodge module is exceedingly useful, and still hard to make, due to the necessity of Cyberdisc wrecks needed to construct them.
• The aliens will most often focus their efforts to increase panic on wherever they have the greatest foothold already, such as countries with high panic or sharing a continent with an existing Alien Base.
  • Fighters, Destroyers, and Battleships flying NoE are never landing and will be performing bombing runs. Allowing these to occur unimpeded will spike panic in those countries (though don't expect to stop a Battleship until lategame). If you want to keep these countries from going over the edge, you'll need a healthy stock of interceptors, potentially even multiple continents worth.
  • Likewise, expect to see Terror Ships and Assault Carriers flying around any country that's in the red, as the aliens commit Terror Missions in order to send a country over the edge to withdraw from the Council. A mid-to-lategame air force of Firestorms with all of the relevant Foundry projects could handle these ships.

Strategic Plan

Early Game

In the early months, you'll want to ensure UFOs are downed so you can harvest them for supplies and earn troop XP, and sending 2 Interceptors (occasionally even 3 in the worst case) to each Scout or Fighter that you find on Aggressive stance is your best bet. To do so, you'll want to buy many interceptors, more than the 6 slots you have available in your starting continent, using other continents to store interceptors as backup and perform lengthy (>15 day) repairs while your starting continent remains stocked with 4-6 interceptors ready to handle any back-to-back UFO contacts. Each early UFO contact you down will practically pay an entire Interceptor in corpses and materials, though you obviously need to save some of it for research and production.

That being said, your goal should be to stack kills on a small handful of interceptors (up to 10 kills per Interceptor) by having it finish off UFOs softened up by others. Interceptor Pilots gain +3% hit chance per downed UFO, up to a maximum of +30% at 10 kills (they also get +1% damage per kill with no cap). Once your Interceptor is getting a cool +15-30% aim bonus, you can switch them over to Balanced or even Defensive to reduce damage and repair times to the interceptor while still ensuring UFOs are downed, or even outfit it with upgraded weapons to take on tougher UFOs.

You start with Avalanche and Stingray missiles as potential armaments. These will work for all small and a few medium UFO contacts, until Aliens stockpile enough resources and/or research to field better UFOs. Avalanche is effective against the unarmored Scouts, while Stingray are optimal for the moderately-armored Fighters.

Scouts will be sent out regularly to attempt to locate your Satellites, anywhere from 3 in the early months all the way up to 6 later on. UFOs on Scout missions (i.e. the mission type, not the UFO type) can be easily identified as they'll be flying Low. Ideally, you'll have 2 Interceptors armed with Avalanche missiles at all times to down any Scouts that show up. If not, they have a chance to fail in their mission both randomly and as a result of damage (dealing at least 50% damage to a Scout will guarantee it fails its mission). If the scout mission is successful, they'll spawn a Fighter shortly afterwards to shoot down the Satellite, which you'll have to intercept with probably at least 2 Stingrays or lose the Satellite.

Even if you've shot down all the Scout ships that showed up, occasionally the aliens will send Fighters to target your satellites directly. UFOs on such Hunt missions can be easily identified as they'll be flying High and flashing purple on the radar screen. Much like Scouts, they have a low chance to fail outright that increases the more damage you inflict to the UFO, with a guaranteed fail after 50% damage. If you've done a decent job shooting down UFOs in the first month (and thus have got the attention of the aliens), you'll typically see at least 1 Hunt mission starting in the second month, which will require at least 2 Stingray-armed Interceptors to down, possibly 3. Expect to see a second Fighter show up occasionally by the third month if you're doing a good job downing UFOs. For more information on how many of each mission spawns, see Alien_Missions_(Long_War)#Mission_Occurences

As an aside, when you down a UFO and successfully assault it, you'll unlock a UFO Analysis research project associated with that UFO type. Completing it will grant your interceptors a nifty +10% damage bonus against that UFO type and also award you +20% extra materials (elerium and alloys) when you assault it with your ground forces. While taking a pitstop to research a UFO Analysis might delay other crucial research, it's quite useful to grab the analysis project when you have the chance, particularly for UFOs you either encounter frequently (Scouts, Fighters, and Raiders in the early months) or currently have the military capacity to shoot down (based on this guide). You'll get a nice boost to your economy and air game if you do so.

Anyways, Raiders are a Medium-sized UFO that will tend to start showing up around June, either in place of Scouts or Fighters. Both Avalanche and Stingray are equally mediocre at dealing with Raiders, although 3-4 interceptions on Balanced will usually do it (good luck finding the engagement window for that though, and be prepared to cripple your Interceptor Bay). You can avoid Raiders on Scout missions if need be, as they'll probably spawn a Fighter to follow up which is easier to kill, but Raiders on Hunt missions will cost you a stack of $200 credits to replace that Satellite if you don't at least cut it to 50% HP. If you can develop the military capacity to down them, it offers more aliens to defeat and more materials to harvest.

If you want to reliably down raiders, you can build a Phoenix Cannon or two once you research Alien Materials. Not only are they equally good as if not better than the other two weapon types you have access to (Avalanche and Stingray) against both Scouts and Fighters, they're also decently better than both against Raiders. Two will usually be sufficient to take out a Raider on Aggressive; you could instead go Balanced, but you'll probably have to send an Avalanche or Stingray to clean up. Four Interceptors armed with Avalanch missiles and two armed with Phoenix Cannons is a versatile Interceptor setup for the early game that should be able to take on two Scouts as well as either a Raider, Fighter, or third Scout in a short window. It's entirely reasonable to build no Phoenix Cannons at all, though, and instead just rush Laser Cannons, which are the strongest against all three types.

Additionally, the aforementioned Alien Materials research will also unlock the Aircraft Boosters foundry project. These allow you to build and deploy three different single-use consumables to boost an individual engagement. Boost Modules (aka "UFO Tracking") are available immediately at the lowest cost, requiring two Drone wrecks and a small amount of cash and materials; they freeze the engagement timer for 5 seconds, giving you extra time to finish a contact. I'd keep a floating stock of a couple of these, and use them liberally in the moments just before you run out of time if you need an extra couple seconds to finish off a UFO. Once you've autopsied a Floater, you'll get access to Aim Modules (aka "Uplink Targeting"), which are a little more expensive and also require three Floater corpses (which are used for quite a number of other things, mind you); this module causes your next two shots to automatically hit, but the booster cannot be used while on Defensive stance. Lastly, autopsy a Cyberdisk Wreck and you'll unlock access to the most expensive module available, the Dodge Module (aka "Defense Matrix"), which requires the most resources including the relatively rare Cyberdisk Wrecks; it causes you to automatically dodge the next two attacks, but the booster cannot be used while on Aggressive stance. You probably won't have enough resources to use either Aim or Dodge modules as liberally as you will Boost modules, so I would save them for taking on particularly dangerous UFOs (see below).

The Laser Cannon becomes available after researching Advanced Beam Lasers; they are highly accurate (with +15% more accuracy than other interceptor weapons), fast firing, and powerful weapons, and synergize well with Defensive stance: a single experienced pilot (5+ kills) can reliably down Scouts solo, and has a good shot at taking down Fighters and Raiders too, all while taking minimal damage in return. You'll want Laser Cannons on as many of your Interceptors as you can afford; ensure your best pilots get Laser Cannons first and feed them even more kills, up to at least 10 each to maximize their accuracy.

If you research Alien Computers relatively early (note it requires 4 Flight Computers) and then autopsy a Seeker, you'll unlock the UFO Countermeasures Foundry project, which will reduce enemy UFO accuracy by a further -15%; combine this with Defensive stance, and small enemy UFOs will be looking at a piddly 3% base accuracy (though keep in mind they get +2% accuracy every 30 points of Alien Research, which at bare minimum increases by 1 per day). If you can outfit your entire Interceptor Fleet with Laser Cannons (a costly endeavor, to be sure), then the combined bonus to your aim (from lasers) and penalty to their aim (from Defensive stance and UFO Countermeasures) will make Scouts, Fighters, and Raiders a joke to deal with. These will be the vast majority of contacts you face in the early and mid game, and you can easily defend an entire continent with just 3 Laser Cannons on Defensive. Your high kill (8+) interceptor pilots should probably be put on reserve to tackle Raiders and potentially even Destroyers, while low kill pilots can be trained up on Scouts and Fighters. At this point, you'll have almost everything you need to dominate the skies for quite some time, and the goal from here on is to maintain this momentum.

Mid Game

When you upgrade to Advanced Gauss Weapons, the Enhanced Coilguns Foundry project becomes available, which significantly boosts the damage (+64%) and armor penetration (+65%) of your Phoenix Cannons (assuming you built any). While the accuracy boost that Lasers provide makes them incredibly useful for the small UFO types, Coilgun-upgraded Phoenix Cannons can be used for the larger, heavily armed UFO contacts. You won't spot them often and you could probably eat the loss associated with just not having the military capacity to handle them, but the option is there.

In this case, with just the Phoenix Cannon upgrade and nothing else, your mid-tier pilots should be able to take on Destroyers and Harvesters. There isn't much reason to down a Harvester, as they always fly NoE and land, allowing you to assault them directly. Destroyers, on the other hand, are high priority targets. These Medium-sized ships may appear in place of Raiders and Fighters around July if the aliens have high enough resources, to either Hunt your UFOs or Bomb cities, spreading panic. They're heavily armored, but one or two decent (3+ kill) pilots with Coilgun-upgraded Phoenix Cannons should be able to down them, as can two or three elite (~10 kill) pilots with Laser Cannons. Aim and Dodge boost modules are a really good investment here to keep your Satellites from being shot down and earn you a juicy medium UFO crash site to raid for supplies, but keep in mind you need to be on Balanced stance if you want to use both.

Bomb missions spike panic in the country by +8, plus an additional +2 if the UFO is completely ignored. Unlike Scout and Hunt, which target XCOM operations directly and show up regularly from the beginning of the game, Bombing missions show up later and tend to target countries with high panic as well as those near their established holdings. As you expand out of your starting continent to new locations with much higher accrued panic, you'll most likely start to spot Fighters and Destroyers (and eventually, Battleships) showing up to Bomb high panic countries. You can identify a bombing run if you spot any of those three ships flying NoE as these ships never land and will flash purple on the radar similarly to UFOs on Hunt missions.

The Advanced Aerospace Concepts research project, available in the midgame, will unlock various foundry projects, such as Penetrator Weapons (+25% Armor Penetration), Wingtip Sparrowhawks (add automatic half damage Stingrays to all Interceptors), and Advanced Avionics (+10% accuracy). With all three upgrades, 1-2 decent (3+ kill) pilots armed with Laser Cannons can imitate the offensive capabilities of the Coilguns upgrade and take down Destroyers. Likewise, consider acquiring the Armored Fighters (+1000 Interceptor HP, from 2500 to 3500) to directly increase the survivability of your aircraft vs. UFOs (and also indirectly reduce their repair time, as repairs are proportional to percentage of damage taken).

With all of these upgrades, shooting down Abductors, Troop Transports, and Terror Ships becomes possible with 2-3 Coilgun-upgraded Interceptors, though again keep in mind doing so is more of a luxury than a necessity. Abductors always fly NoE and usually generate Abduction missions for cash rewards (although they may also land normally and allow you to assault them in rarer cases); you might consider shooting them down for the alloy and elerium salvage, rather than letting them land for cash. Transports typically fly NoE and land, allowing you to assault them, though on occasion their appearance flying Low (especially while joined by a Battleship) signals an infiltration mission that will instantly force a country to leave the XCOM project. Preventing this is impossible unless XCOM has a Hyperwave Beacon to spot the hidden Overseer the two UFOs are guarding, but fortunately, Infiltration missions are rare unless XCOM is quite far behind the aliens, and you can always assault bases. Lastly, Terror Ships will serve as an advanced warning for an incoming Terror mission as they screen the airspace in advance of an Assault Carrier. Shooting them down won't stop the Terror mission, but you'll be able to get a lot of good rewards from it if you can manage to do so and cost the aliens dearly for every terror mission they run. Keep in mind that all of these UFOs will be armed with the incredibly powerful Double Plasma, which has +7% higher base accuracy, 8% faster fire rate, +20% armor penetration, and nearly double (800 vs 450) the damage per shot of a regular plasma. A single extremely lucky crit from these things can potentially one shot kill an interceptor without Armored Fighters, so always make sure you grab that before trying to take on large UFOs.

Eventually, you'll unlock research of Advanced Pulse Lasers and the Supercapacitors Foundry Project. This provides a similar boost to Laser Cannons that Improved Coilguns did for Phoenix Cannons; this time, you're looking at a minor increase in damage (+3%) but a significant increase to armor penetration (+30%) and fire rate (+33%). Your Laser Cannons will now outperform Coilgun-upgraded Phoenix Cannons (assuming you have any, as well as the associated upgrade) against most of the above UFOs, but your Phoenix Cannons will still be optimal any time you feel like trying to take down a Terror Ship or Abductor. As previously mentioned, you don't *have* to shoot down these UFO types if you don't want to.

You'll also be able to construct Firestorms once you research Alien Propulsion, which provides a considerable upgrade over the basic Raven interceptor: they come with +1500 hp, +25% Armor Penetration, +100% Armor, and 50% faster flight speeds (letting you reach the UFO faster and also granting you 50% longer engage times); additionally, your most experienced pilot will automatically move into the new craft (bringing their accuracy and damage boosts with them, but leaving the weapon they were armed with behind), and a rookie pilot will to take over the Raven they leave behind. The additional armor penetration pushes Laser Cannons ahead of Phoenix Cannons against all aforementioned targets, and in conjunction with the improved survivability will make Laser Cannons quite effective against all aforementioned UFOs.

Additionally, Alien Propulsion also unlocks the Elerium Afterburners Foundry project, which increases your interceptors speed by +5; the easiest way to think about this is a +50% engagement time boost to your Ravens and a +33% engagement time boost to your Firestorms. It doesn't much help if you're outgunned, as it doesn't improve your survivability or damage; if you have to abort early, it does nothing for you, and it's not going to shorten your repair times either. What it does do is twofold: first, you can dish out more total damage over the same number of engagements, which helps against fast or tanky UFOs that escape into orbit before you can finish shooting them down. Second, you also concentrate repair times on a single Interceptor, which can be both a blessing and a curse. You can't use Interceptors to shoot down UFOs while they're damaged, so having 4-5 lightly-damaged interceptors means you're vulnerable to attack for a short window. Conversely, 4-5 lightly-damaged interceptors can all undergo repairs simultaneously, so you'll get them all back sooner than a 1-2 heavily damaged ones.

Late Game

One to two Firestorms piloted by top pilots (10+ kills) with all the aforementioned Foundry projects to boost them (including either Supercapacitor Laser Cannons or Coilgun Phoenix Cannons), plus a healthy selection of boosters for insurance will be able to take on Assault Carriers. These are the third-strongest UFO in the game but have a small chance of dropping Fusion Cores when shot out of the air, making downing them well worth it. They're also responsible for dropping off the troops for the most difficult missions in the game, namely Terror and Retaliation missions, and shooting them down means you completely avoid said mission. You'll have a short window to spot and engage them before they arrive at their destination, and nothing short of shooting the UFO out of the sky will have any impact whatsoever.

To finish the game, you'll need to find and shoot down an Overseer. Overseers are hidden on the geoscape until you construct the Hyperwave Beacon, after which you'll see them floating around the geoscape conducting Command Overwatch missions. These missions don't have any mechanical impact on the strategic layer like other missions do; they're just there to allow XCOM the opportunity to shoot an Overseer down. Once you do spot one, you'll find they're extremely fast, heavily armored, and equiped with solid armaments. Their speed makes it difficult to catch them in the geoscape and gives you an extremely short window of engagement once you do engage them; Firestorms, Elerium Afterburners, and Boost modules are all quite useful here, and you'll probably only get a single engagement. Similarly, their extremely high armor renders Lasers impotent against them; if you're trying to shoot them down without end-game interceptor weapons, you'll need a Coilgun-upgraded Phoenix Cannon mounted to a 10+ kill Firestorm plus every single aforementioned UFO upgrade and a full set of 3 modules to stand chance, and even then you need to get lucky with your engagement (or get a second engagement). Plus, you can never predict which continent the Overseer will appear in, so unless you want to pray to the RNG gods for month after month you'll want to develop the capacity to down an Overseer in multiple continents, not just one.

For a more reliable method of downing an Overseer, you'll need either Plasma Cannons, EMP Cannons, or Fusion Lances on your Firestorms. Once you're most of the way through Plasma tech, Vehicular Plasma will unlock Plasma Cannons. Each Cannon requires an intact Alien Rifle to build, which are equipped by mid-to-lategame Mutons and Heavy Floaters; you can only acquire intact enemy weapons by capturing the enemy unit alive with the Arc Thrower (you'll need to do a lot of this in general to make Plasma tech). Your best pilot in a Firestorm with all upgrades and a Plasma Cannon could be expected to easily solo an Overseer; you might want to bring two if you want to take on a Battleship though. Speaking of which, Battleships are the penultimate UFO type, and are fielded in many types of UFO missions we discussed previously (Scout, Hunt, Bomb) whenever enemies have a glut of resources or in the lategame when they've accrued large supplies of resources (as mentioned previously, they'll also appear during Infiltrations). These things come armed with a Fusion Lance that deals 1200-1600 damage per shot at base, and 2400-3200 on a crit, which is over half the HP of a Firestorm with Armored Fighters. You remember what it was like to fight Scouts with fresh pilots flying Ravens? Welcome back to March, boy.

Electromagnetic Pulse Weapons is an earlier alternative to teching heavily into Plasma, and is available after you've researched both Gauss and Pulse lasers. Unlike Plasma, you don't need a large assortment of captured weaponry to research and outfit it, but Plasma also upgrades your ground forces, and is pretty important to tech into before you finish the game. In any case, the research will unlock the EMP Cannon, which has low damage per shot, extremely high armor penetration, and a fast fire rate; the net result is moderately worse performance compared to the other two end-game weapons against virtually all UFOs (except Overseers, actually), but they're also the least likely to overkill and destroy the UFO outright, and they also have an innately reduced chance for UFO components like flight computers, fusion cores and power sources to be destroyed on crash; if you want to farm UFO components and resources its... well kind of a luxury item, really, since it comes so late and is so expensive, but it's there.

EMP will also enable research into Fusion Weapons, which will unlock the Fusion Lance. They are the most powerful Interceptor weapons in the game and can only be mounted on Firestorms, but consume a rare Fusion Core to do so; it can be quite difficult to acquire these, but shooting down Assault Carriers with an EMP Cannon is your best bet (or just save a spare core from the Slingshot DLC mission). Much like EMP, it's a luxury weapon, but a Firestorm mounted with a Fusion Lance can utterly dominate the skies; once acquired, you can solo any UFO type you feel like for quite a while. That said, keep in mind the free bonuses enemies get over time (+75 HP, +8 damage and +2% aim every 30 days, or more if enemies accumulate large amounts of Alien_Research_(Long_War) will eventually stack their accuracy all the way to the cap of 95%, so you'll need to make an effort to finish the game before that happens.

Damage Calculations

• Armor Mitigation = Target Armor - Armor Penetration [%]
  • 0% is the minimum Armor Mitigation and 95% is the maximum
• Base Damage = Weapon Damage * (1 - Armor Mitigation)
• Crit Chance = (Armor Penetration - Target Armor) / 2 [%]
  • 5% is the minimum Crit Chance and 25% is the maximum
  • A successful Crit multiplies damage by 2
• Total damage is then randomized to between 100% and 150% of its current value
• For XCOM Aircraft:
  • If the appropriate UFO analysis has been researched, total damage is multiplied by 1.1
  • Total damage is also multiplied by 1 + (Pilot Kills / 100)

Examples:

• Avalanche Missiles (340 damage, 0% armor penetration) vs Fighter (armor 60%): no armor is penetrated, so 60% of damage is blocked, and the Avalanche has an effective damage of 136-204.
• Laser Cannon (290 damage, 25% armor penetration) vs Fighter (armor 60%): effective armor mitigation value of 60%-25%=35%. Consequently, 35% of the damage is blocked, and the Laser has an effective damage of 188-282.
• Stingray Missiles (200 damage, 50% armor penetration) vs Fighter (armor 60%): armor mitigation value of 60%-50%=10%. Only 10% of damage is blocked, the Stingray has an effective damage of 180-270.
• Avalanche Missiles (340 damage, 0% armor penetration) vs Overseer (armor 200%): 200% damage blocked (nonsense) gets corrected to 95% damage blocked, effective damage is 17-26.
• EMP Cannon (310 damage, 150% armor penetration) vs Scout (armor 0%): armor mitigation is 0%-150%=-150%. However, damage is never increased due to penetration, so this gets corrected to 0% resulting in effective damage of 310-465.

Note that in the above example while the Laser Cannon and Stingray Missiles are about equal on a per-hit basis, the Laser Cannon is more effective in combat due to its higher rate of fire and higher accuracy.

Tables

UFO Types

UFO Type	Health	Armor	Penetration	Firepower	Description
Scout	750	0%	15%	1x Single Plasma	The speedy Scout-class UFO is fortunately within Earth's native capabilities to shoot down ... on occasion. It appears to be used for general reconnaissance, resource-gathering and research.
Fighter	850	60%	35%	1x Single Plasma	The alien Fighter, while similar in outward appearance to the Scout, is much better protected. Armor-piercing weapons like our Stingray Missiles will be helpful in bringing these craft down. This class of craft is used primarily for air raids and anti-satellite operations.
Raider	1500	25%	35%	1x Single Plasma	The Raider class of UFO seems to be a multirole craft that thus suffers in combat power. The aliens appear to use it for reconnaissance, research and resource-gathering operations.
Destroyer	1600	90%	75%	1x Single Plasma	The deadly Destroyer present a much greater threat to our aircraft than its sister class of ships. Armor-piercing weapons are required to defeat this craft. It appears to primarily be used for air raids and anti-satellite operations, although we may see it conduct reconnaissance missions as well. Our analysts note the presence of unused hardpoints on some images of this craft, so we should look out for upgraded versions with even more killing power.
Abductor	4000	160%	10%	1x Double Plasma	Abductors appear to be much better protected than other ships of this size. Perhaps the aliens particularly value the abduction and research missions they are used for.
Harvester	6000	100%	15%	1x Double Plasma	The Harvester class of UFO seems to have one role - to recover important biological materials and minerals from Earth in support of other alien operations. We should try to interdict alien harvest operations whenever possible to slow the alien advance. These craft may be vulnerable to a concentrated attack.
Transport	5000	160%	0%	1x Double Plasma	This ponderously slow craft will be a tough nut to crack. It appears to be primarily used in alien terrestrial resource-gathering but could also be used in support of other major alien operations.
Terror Ship	6000	125%	0%	1x Double Plasma	The rarely encountered Terror Ship appears suited for rapid deployment of alien shock troops. They appear to presage alien terror missions, but they may be used for alien research on XCOM as well.
Assault Carrier	8000	140%	90%	1x Double Plasma, 1x Single Plasma	The Assault Carrier, while built on a battleship hull, lacks some of its sister's firepower and may be easier to shoot down. Nevertheless, we expect to see the aliens use this craft only against high-value targets, so it should be taken seriously whenever it is detected.
Battleship	9000	180%	125%	1x Fusion Lance	An unbelievably dangerous piece of hardware, these UFOs never appear to land but are used in bombing, anti-satellite and air superiority roles.
Overseer	2500	200%	125%	1x Double Plasma, 1x Single Plasma	This class of ship appears to be used as a airborne command center for the Ethereal race of alien. Only our strongest weapons will be able to penetrate its armor.

Aircraft

Name	Health	Armor	Armor Penetration	Speed	Prerequisites		Cost						Maintenance
											Other
Skyranger	Can't be damaged or destroyed				XCOM starts with one, unable to produce more								20
Satellite	Increases funding and provides unique bonuses					10	200 (300)			0 (7)		25 days (12.5 days)
Interceptor	2500	25%	0%	10			200					3 days	40
Firestorm	4000	125%	25%	15	Alien Propulsion	75	750 (1125)	180 (270)	120 (180)	10 (30)	8 UFO Flight Computers 4 UFO Power Sources	28 days (14.0 days)	50

Interceptor Weapons

Name	Hit chance	Damage	Armor Penetration	Firing cooldown	Prerequisites		Cost						Sell value
											Other
Avalanche Missiles	25% / 40% / 55%	340 (170 per second)	0%	2.0 second	XCOM starts with an unlimited supply
Stingray Missiles	25% / 40% / 55%	200 (133 per second)	50%	1.5 second	XCOM starts with an unlimited supply
Phoenix Cannon	25% / 40% / 55%	140 (183 per second)	25%	0.75 second	Alien Materials	15	120 (180)	12 (18)		0 (5)		10 days (5.0 days)	48
Phoenix Coilgun	25% / 40% / 55%	230 (307 per second)	90%	0.75 second	Phoenix Coilguns (Foundry)
Laser Cannon	40% / 55% / 70%	290 (290 per second)	25%	1.0 second	Advanced Beam Lasers	25	160 (240)	30 (45)		0 (6)		10 days (5.0 days)	64
Pulse Cannon	40% / 55% / 70%	300 (400 per second)	55%	0.75 second	Supercapacitors (Foundry)
Plasma Cannon	25% / 40% / 55%	650 (650 per second)	110%	1.0 second	Vehicular Plasma Weapons	95	500 (750)	50 (75)	60 (90)	5 (19)	1 Alien Rifle	14 days (7.0 days)	200
EMP Cannon	15% / 30% / 45%	310 (563 per second)	150%	0.55 second	Electromagnetic Pulse Weapons	100	575 (862)	60 (90)	160 (240)	0 (16)	1 Sectopod Wreck	20 days (10.0 days)	230
Fusion Lance	15% / 30% / 45%	1200 (960 per second)	130%	1.25 second	Fusion Weapons	120	800 (1200)	70 (105)	120 (180)	40 (62)	1 Fusion Core	25 days (12.5 days)	320

Modules

Name	Special properties	Prerequisites		Cost						Sell value
								Other
UFO Tracking (Boost)	Increases the duration of this air combat by 5 seconds	Alien Materials Aircraft Boosters	12	15 (22)		1 (1)	1 (3)	2 Drone Wrecks	5 days (2.5 days)	6
Defense Matrix (Dodge)	Dodges the next two incoming attacks	Cyberdisc Autopsy Aircraft Boosters	50	25 (37)		2 (3)	1 (3)	2 Cyberdisc Wrecks	5 days (2.5 days)	10
Uplink Targeting (Aim)	Automatically hits the next two attacks	Floater Autopsy Aircraft Boosters	35	20 (30)	1 (1)	1 (1)	1 (3)	3 Floater Corpses	5 days (2.5 days)	8

See also

• Aerospace Improvements
• Hangar
• UFOs