In GTA San Andreas, there are small blinking lights that can be witnessed flying at a very high altitude at any time of the day. These blinking lights fly faster than any vehicle in the game and they have a very long vapor trail behind them. The player can never catch them, as they fly very fast. The purpose of these lights in the game has been a very hotly debated subject within the GTA Community.
The blinking lights in the sky could have been designed by game developers to look like airplanes. However, it is still unknown if game developers wanted these lights to look like UFOs or not. The only reason players think that they are UFOs is probably because they can never catch them. If the player gets close enough to the strange lights, they will find that they are just insubstantial glowing spheres. In the game files, these lights are called "UFOLIGHT."
These lights can be rarely seen over the desert part of the state as shadows or lights. Nevertheless, it is not known why these strange blinking lights are included within the game, because the game features real solid airplanes that fly regularly over the sky.
In GTA San Andreas, there is a UFO Map of San Andreas inside the Lil' Probe Inn, which appears to be marked with small pins in various places on the map. The map appears to be marking UFO sightings within the state, though there aren't any UFOs, which can be seen here. Interestingly, the same map can also be found inside Mike Toreno's Ranch. An NPC known as Mr. Trenchcoat is also associated with UFOs. He will talk to CJ about them and will talk to other peds about aliens as well.
Snapshot icons usually get confused with UFOs, because at night, the icons emit a bright glowing light, so the player can locate them easily. One example is the Snapshot icon hovering over Missionary Hill in San Fierro. However, most of the UFOs that have been seen look exactly like these glowing icons.
A glitch may occur in Downtown Los Santos, more frequently on the original PS2 version. Sometimes the model of the Los Santos Tower will not load correctly, and the entire tower will be invisible, except for the circular-shaped roof, leading to many misconceptions that the roof is actually a UFO hovering above the city. This phenomenon occurs mostly when the game is having loading problems, or when the draw distance is set to high. Typically, after the player gets closer to the building, the entire texture will load completely. This glitch may sometimes occur with other nearby buildings as well.
- The Lil' Probe Inn contains many photos of UFOs and a map of where they are in San Andreas. It is strangely just down the road from Area 69, which is believed to contain aliens.
- There are modifications that turn the UFO model outside Lil' Probe Inn into a real UFO, complete with lights and sounds.
- During the mission Black Project in GTA San Andreas, while CJ is inside Area 69, various strange announcements can be heard from an administrator over speakerphone, such as "Could the owner of the Alien culture in the diagnostics lab please kindly remove it?" and many other announcements about aliens.
- The only known UFOs that exists, besides the real ones in GTA V, are an undisclosed UFO in the InterGlobal Film Studios in GTA Vice City, and the fake UFO outside of the Lil' Probe Inn.