I guess this is, like, jousting on helicopters? Chicken with helicopters and cars? Whatever this is, it's amazing. And it's all thanks to the crazy minds at Achievement Hunter.
What you do is, basically, lift your best cars up, meet your friends in mid-air and start ramming each other. This would probably make even less sense with tanks or buses, so someone should probably do that.
Things to do in GTA V - Air Jousting [Rooster Teeth, YouTube]