I've heard great things about Bach Rescue Remedy, it's in the health food stores and it's drops for anxiety, all natural. Make sure that you make your reservations well in advance,because planes can only take 2-4 animals each flight, FAA regulations, and you have to make sure to reserve your spot.
The ascent and descent could be hard on his ears, so bringing him a chew toy would be a good idea. They don't let you take them out of their carriers in flight, but we did with Starr, lol! She was crying and I couldn't stand it anymore
Also make sure that he eats, has a drink of water and potties before you go into the airport. They are to be in the carrier the minute you walk into the airport.
Good luck! Starr was a great little traveller, but she preferred road trips
