I was lookin' around at Battleground Halo and I saw a post about there being three Banshees in AotCR, but they didn't know how to get them all. We all know about 1: If I had a Super Weapon and 2: Where you get the tank and the Banshee is up on the platform. I was reminded about how I found another Banshee. Here's how to get it: You need a sniper rifle and a rocket launcher. When you ditch the tank, go up the little zigzag path after the tunnel and take an immediate left to the closest rock on the left AFTER you get up the zigzag path. If you want, you can kill the Grunts w/ a grenade. Well, jump up onto the rock and face the other end of the map. There should be a concrete structure that looks like (here's a good comparison) a brush guard for a truck.
Look at the far right of it with the Sniper Rifle in 10x zoom and there should be a Banshee parked near the cliff wall. Jump up to get the reticle lined up near the bottom of the Banshee. As soon as you get a shot lined up, get your Rocket Launcher and time a shot with the jump. Get out your Sniper Rifle again and zoom to watch the rocket and see if it flips the Banshee. You may have to try several times, but it can be done. When you flip it, run over to it and kill the Elite standing by it and fly up to the bridge that has 1 licked door and go to the other end and your free to finish the level!