When you are in the level where you have to disable the forcefield around the Truth's citadel go thruogh the level as normal.Then when you get the hornet(s) go strait towards the banshees an hornets are fighting. After that try to get directly above one of the banshees.Next you drop out of your hornet and hijack the banshee.

PS.Your timing has to be exact when you drop from your hornet.