I'd be really hesitant about playing in an airplane unless I was playing a solid-body uke through headphones and even then only if the seat next to me was empty. Doing anything that makes noticeable "noise" on a crowded flight where people can't get away is just downright rude - no matter how accomplished you are as a player. I put doing that right up there with the obliviots who insist on yammering on the phone in public places where audiences are "captive."
Back in the mid nineties I had a flight from Milwaukie (sp?) back home to DFW. I'd been sitting in the gate area waiting for this flight - the area was packed and there were no other seats so I was basically stuck a few seats away from a couple that was arguing loudly and incessantly about family matters (whether some other relative was worth the air he breathed). The quarrel went on, and on, and ON, AND ON. We boarded the plane and, yep, guess who was seated right behind me. They never even stopped arguing all the way down the jetway and to the seats as we boarded the flight. I was contemplating whether I could endure a three-hour flight sitting in front of these obliviots without comitting homicide when the flight attendant announced that the flight was overbooked and they were asking for volunteers willing to spend the night and catch the first flight out the next morning. They ended up with more volunteers than were needed - fortunately, I was the first and had not only raised my hand, I'd jumped out of my seat, grabbed my carry on, and headed for the front of the plane.
When you're in any situation where people can't escape your presence, the only courteous thing to do is make your presence as unnoticeable as possible.
Just my $0.02,
John
