I would take off the pedals, loosen the screws for the rear derailleur and take a bread tie or rubber band and secure it to the bike, keep the cables attached, but loosen the handlebars, take off the seat post and wheels, and possibly take off the freewheel, if it doesn't fit after you put the wheels in.
I've had to take my bike apart more times than I've cared to in the past for air travel. *sigh*
Koffee