The Warthog Jump was first recorded by Randall Glass. It is commonly done in Silent Cartographer, where you launch a Warthog into the air using grenades and/or rockets. In Halo 2, the Sputnik Skull can be used to make Warthogs fly farther than they would normally. In Halo 3, through use of the Forge you can put a Warthog on top of a pile of Fusion coils, though this normally destroys the warthog, however, the wreck may fly a good distance. You could always change vehicles to indestructible in the pregame lobby to enjoy the effects of flight.