The Nemesis is required for this trick, and is very difficult to execute. Have your pilot hover slightly below the edge of a cliff and have the jeep(s) drive onto each wing. You can get two jeeps on at a time. Like the troop riders, jeeps will make your plane sink. Quickly press R2 to go up and keep from sinking. Jeeps can also be dropped from high altitudes with little or no damage. It is very effective to have two jeeps with people in the turrets. Also, a person with a rocket launcher can crouch on top of the jeep.