Bungie's last update
gave us a hint about something every halo player has wanted to do since Halo CE: drive a pelican. Well it wasn't long after that hint dropped that the HIH community at large was on the lookout in New Alexandria for the chance to drive a pelican. Sadly, soon after the announcement, information was released as a result of digging through the game code, which takes away much of the thrill of the hunt for many egg-loving fans. However, the HIH community found that you just had to fly over to another building after activating the switch and you would be transported into either a pelican if you were flying a falcon or a phantom if you were flying a banshee.
Read all about it in Spec Ops Lead's thread
EDIT by Duke: I only very slightly changed his original post - thanks much for the writeup!