Riding a Pelican

Play through the Metropolis (Level) until you get to the part where you're in a Gauss Warthog with another Warthog riding alongside you (your situation may be slightly different, but that's what is meant to happen). You come into a street with a couple of Jackal snipers, two Wraiths, and a couple of Ghosts. Another Wraith and two Phantoms come momentarily, followed by two Pelicans.

Notice where the Jackal snipers were standing: raised areas between the streets. Go to the far one. This is the point where the Pelican will drop off some marines for you. Be at the top of this area before the Pelican begins its descent.

As soon as the marines have exited the Pelican, jump toward the passenger bay and hold the X button. I suggest aiming for the bottom of the Pelican, right near the back entrance. This should allow you to climb aboard and go for a ride.

After a short trip, the Pelican falls to the bottom of the level. In Halo: Combat Evolved, a free-falling Pelican would travel the exact same path every time, but things might be different here. When I did this in single-player mode, two marines, the Pelican, and I all landed safely at the very bottom of the level. In the three times I've tried it in co-op mode, though, everybody landed on a giant concrete platform (too far down to get back into the level, and too far up to continue to the very bottom). The Pelican continued its way down, while we were stuck there.

If you manage to get to the bottom (blue area), you notice two pretty interesting things. The first is that the Pelican lands facing up, or keeps rocking back and forth until it looks straight up. The second is that when you walk up to it, it says, "Press X to flip Banshee." Banshee, huh? Yeah…

Also, if you jump onto the rooftops at the beginning of the Outskirts (Level) and completly blow off the battle in the first part, a checkpoint will appear and Sergeant Johnson will spawn and begin boarding a Pelican which will also come. If you jump onto the Pelican it will fly off with you on it. You won't get far though because it disappears in mid-air!