You can collect spaceship parts in GTA V. You can even spot some UFOs in-game, if you play your cards right. But now modders have found a way to make spaceships actually playable in GTA V, which is amazing.
You can see the mod in-action in this footage by TwoDynamic — mostly, he just flies around Los Santos, but still! It's the same spaceship you can see in Mount Chiliad, when you get 100 per cent completion in the game.
And if you're wondering how this is possible, given that there's no PC version of the game out: they're using a modded PS3, where they reconfigured some files such that vehicles can transform into the UFO. You can see this happen in this video by Mark Rosette Ecb:
The question is: which is better, UFOs or spider mechas?