I'm sure he did that, but the real question is: even if you skip enemies and what-not, how do you get one Banshee to the bridge and then use a different Banshee to do the trick? It should be nearly impossible to get back down from the bridge once you're on it, and it seems like that would be the only way to go. Otherwise you have to somehow get two Banshees up there at the same time and then use one to leave while the other one stays, which is of course nigh impossible. Now, you could be asking yourself "Why don't you just use one of the doors and then come back down the elevator to reach the ground level?" The problem with that is, the door to the elevator area, if I recall, is actually shut tight until you trigger all the previous stuff. The reason for this is unclear, but it certainly is an obstacle. Thus, the only options I can see are flying up and then falling down. It should be obvious why this is a problem.

Bungie seems to have gone to great lengths to stop us from playing with disembodied dropship turrets. ;)

Vale,
Perseus