J.B.
Hi! Does he like to watch DVDs? We just flew to Phoenix and the only thing that got my wigglemuffin to hold still was watching her Baby Einstein DVD on Daddy's laptop. They also sell those little handheld DVD players.
Another bit of advice? If you're planning on keeping him in your lap, do whatever you have to do to upgrade to first class. (I bought frequent flyer miles from my husband to do it.) The extra room makes all the difference when they're wiggly.
Even better yet, if your flights aren't full, you can get a seat next to an empty seat and put him in the empty seat IF you have a travel-approved flight seat. Check out the Sit N Stroll if you haven't already; this thing is a LIFESAVER -- combined stroller, FAA-approved flight seat and carseat. I borrow my girlfriend's every time we travel.
Hope this helps!
J.