I used a tough, plastic carrier. Do remember that some airlines have not only limits to the size of the carrier, but also to the weight of the cat itself. To sedate or not. My vet advised me not to sedate Zeerox, nor to give him anything against air sickness. I would not try to sedate a reasonable relaxed kitty just 'as a precaution'.
Some cats even get more hyper from valium.
A couple of things to do not to upset the cat are to give him some practice with travel and the carrier, to speak to him calmly, and very importantly, not to get upset yourself. A cat might not see anything scary out there, but if you are tense and upset, he will pick up on that. If your cat is a very nervous type, I would ask advise from a good vet, and not just give him some 'over the counter' sedative. Food and water. I have not taken Zeerox off food and water before the trip.