Fly ontop of building with banshee
To do this get the banshee(duh)and aim at the building you wish to fly on. (NOTE: It cant be TOO high.) Aim almost all the way up and fly twards it fulls speed with out using the boosters. You should be going really slow because you are facing up.

Golden Warthog Video Clip [Download] Note: WE DONT KNOW HOW TO DO THIS.

Goto the side of the base, the place with the 4 plasma nades and the loading depot. Have one person go between the 2 pillars. Have a wrath launch him. Also works with a hog. Hog Vid https://www.youtube.com/watch?v=ppTxw6iBBkE

Ghost Launch

Have someone in the ghost goto infront of the base and line up on the number there. Have a wraith line up and ram him. Video: https://www.youtube.com/watch?v=110CSGEuLrU