UFOs (EU2012)
The UFOs seen in the skies of Enemy Unknown (2012) have functional shapes. They are able to fly at breakneck speeds through the power of Elerium and the resiliency of Alien Materials. UFOs come in a variety of forms ranging from the tiny Small Scouts right up to the massive Battleships.
UFOs are the aliens' sole method to get to Earth, so in theory, it would be possible to halt the alien advance if XCOM could maintain absolute air superiority using its interceptors and satellite network. Earth's forces do not initially have the resources required for such a task, and even if it becomes possible, the aliens should have a vast resource supply and will not be set back by a war of attrition. In addition, alien undercover agents will continue to erode Earth's defenses from the inside.
Despite this, commanders should still shoot down as many UFOs as possible. At the very least, it may slow the aliens down temporarily. In the long run, it will actually further antagonise them, causing the aliens to accelerate their agendas. In any case, captured alien technology is essential to our research and finances.
UFO Types
The UFOs deployed by the aliens range in size and the mission profiles they are most commonly seen on, some are also much more common to certain of the alien races encountered.
Very Small UFOs
Small Scout - Very Small UFO. Primarily used for research.
Small UFOs
Medium Scout - The classic 'flying-saucer' craft. Able to fill a variety of roles.
Large Scout - Slightly larger than the Medium Scout. Very versatile.
Medium UFOs
Abductor - Medium-sized UFO used primarily for human abduction and experimentation.
Harvester - Medium-sized UFO with food and surgery units. Used to abduct cattle for food.
Large UFOs
Supply Ship - Large-sized UFO for transportation of aliens, food, and other supplies.
Terror Ship - Large UFO used to unleash alien terror teams on residential areas.
Very Large UFOs
Battleship - Very Large UFO used to intimidate Earth's peoples and leaders, and to retaliate against X-COM, along with a variety of other roles.