I prefer these for air travel. The door latches up and down as well as across it. I find them to be the sturdiest. It is what Judge's breeder uses to ship GSDs internationally.
The other thing I'd use when flying is hand-releasable zip ties:
http://www.dryfur.com/hand_releasable_cable_ties.htm
They have them there, or you can just buy them in a hardware store. Use them to secure the door, and they can easily be removed when you get there.