Banshee Jumping

Banshee Jumping (also known as Banshee Launching) is the art of projecting your player into the air using a Banshee as a make-shift catapult.

Directions
The best results are achieved with an overshield and a rocket launcher. Flip the Banshee on it's side so one wing is on the ground and the other is pointing into the air. While standing on the very tip of the wing (the circular section), aim and fire a rocket at the other wing's tip, causing the vehicle to flip and catapult you into the air.

You can use this method to reach the top of some of the buildings in Headlong in Halo 2.