I flew Continential with my cat about five years ago. You need an airline approved cage that will fit under the seat. I got one at Pet Smart. It was just big enough for kitty to fit in and he had to lay down the whole way, but he did fine! Please note, you must make a reservation for the animal as well as yourself--the airlines limit the number of animals in the cabin. Also, there is an extra charge for the animal. I believe I paid about $80, but , of course, it depends on the airline. The cage would probably fit under the seat in coach, but it would be tight. I upgraded to first-class (used dh's ff miles!) and had much more room. I could reach down and pet kitty through the cage. In coach, he would be wedged in to tight for that. I did encounter a problem with security (this was pre 9/11) The lady at security wasn't helpful at all and insisted I take kitty out of his cage and walk through the metal detector with him. I explained I was hesitant to do so, because he wasn't on a leash and might bolt. She the proceeded (without my permission) to put kitty, cage and all, through the metal detector! The poor animal must have been terrified! Not to mention the radiation he was exposed to! I would make sure to have your cat on a harness and have a leash you can attach if you encounter such a problem with security. Of course, don't attach the leash while in the cage or he could get tangled up like that. My vet wouldn't prescribe a tranquilizer, either. Said it could cause a bad reaction. However, kitty did fine and didn't cry or howl the whole trip. A much better way to transport an animal rather than in the luggage hold, not so hot, and you can keep an eye on him the whole way. Good luck!