X-COM Hybrid Aircraft (Apocalypse)

With the help of a few UFO bits, a warehouse of Nutrivend synth'o'cola™ and lots of duct tape, X-Com researchers have been able to reverse engineer the UFO engines (which appear to be of alien origins even to the aliens) and the transdimensional gate navigational systems and integrated them into our own home grown vehicles.

Because energy is drawn from the alien world on the other side of the Dimension Gates, hybrid ships never run out of fuel and can stay on sentinal duty for days on end - unless the gates are closed abruptly, in which case the ships would plummet to their doom.

Dimension Probe

An unmanned prototype ship that can arm light weapons. Although originally meant to be a one-shot throw away ship, it never needs to be built. It can also double as a slightly expensive interdimensional hoverbike replacement. It is also the fastest ship available.

Bio-Trans

The Bio-trans is a flying hearse van designed primarily for transporting agents, aliens or equipment to and from combat sites. It is not designed for combat but can mount sufficient countermeasures to keep troops relatively safe from harm (in the form of shields - lots of them).

Explorer

The Explorer is the first ship designed with combat in mind. It is a fast interdimensional variant of the Hawk Air Warrior with slightly less module space. Weapon hardpoints include one main cannon and two additional smaller weapon hardpoints. Although not comparable to the Annihilator, this ship can take on anything given sufficient numbers.

Retaliator

The Retaliator is a minor step up over the Explorer where it can mount three main guns and has as much space as a Hawk Air Warrior for upgrade modules. It's basically a ship with three times the firepower of an Explorer.

Annihilator

The Annihilator is the be-all-and-end-all of the interdimensional gunships. It mounts two main weapons and a grand hardpoint suitable for the Large Disrupter Beam cannon arrays found on alien capital ships. It contains enough upgrade module space to expand the ship to take on other roles such as a heavily armoured troop transporter if the need ever arises. Otherwise it's clearly designed as an all-out assault vehicle that's meant to be fitted with a huge array of large and small disrupter shields. A single Annihilator controled on manual is quite capable of easily leveling the entire city, although as amuseing as that may be, its not exactly what your being payed for.