I flew from Chicago to New York with a mama cat and kitten in one carrier. The whole ordeal took about 11 hours considering the flight was really delayed, then I had to hop on the train once I got there, etc. Like others have said, you have to get a health certificate from your vet that's within 10 days prior to travel and make a reservation with the airline, pay a fee (I think I flew United and paid $80 per cat), etc.
My cats were extremely well behaved the whole way. I took them in one of those mesh carriers and held it in my lap the whole flight. The only time I shoved them under the seat was during take off and landing. They barely meowed. I also wanted to add that everybody at the airport and on the plane were really nice about they whole thing. In general, people were very amused about the kitties, and when I had to take them out to get through security, the security people offered to hold them, everybody was awwing at them.
One last thing, you should obviously check with your vet, but I don't think it's such a great idea to sedate your cat. I think something happens with the change in pressure and their breathing that can make sedation kind of dangerous.