If you read the flipping elephant cheat, this is a bit like that one but all you need to do is use trip mines under the whathog.

It needs a lot of trip mines, I would wod put down 10-20 trip mines then get in the passenger side or if you want let your friend go in the gunner side.

Then let the passeager shoot the trip mines and you'll go fliying across the map.

PS: do it on Sand Trap, it's the only map big enough to do it.