you can do a simple one with pictures that you download (or maybe people send to you electronically.) PM me if there is any in particular and I can send them to you when we get back. Simple language, just to let him know what to expect.
We were more into prepping our kids for the airplane ride. STILL nervous about that! We did some airplane games (lined up chairs like an airplane, then took off, leaning the chairs back, threw in a little turbulance for fun!) Then last Friday, my sons therapists, their sister and I went to our airport, which is only 10 minutes from our house. BWI has an observatory for kids, so we did it like a scavenger hunt. Each had a list of things to find (moving sidewalk, elevator, suitcase, ticket agent, telephone, screens for departures/arrivals, etc. etc.) The kids LOVED it. I am glad we did it close to the trip, because my one guy went running to the car the other day with his suitcase!
Good luck!