I haven't flown anywhere since being this ill, but I did purchase one of those back massagers for seats. I find this handy when traveling by car. It plugs right into the cigg lighter...heats and vibrates.
I hope you have a safe and enjoyable trip.
Well, I hate to throw this one out there, but I use drugs. I very seldom take opiates - but when I'm travelling? Bring them on. I want to go out and enjoy it and manage to do things and the only way that I can flog my body through that is to take them. Oxycodone to be exact.
The other thing is to phone the airline 2-3 days before you fly and let them know you need assistance. They'll buggy you everywhere. It's better than trying to exaust yourself by walking.
Only other thing I can think of is to get those stick on hot patches and do your problem areas - for flying that usually becomes my hips. But everyone is different. Don't forget to keep drinking water even though it's a pain (and expensive) around airports - very important to keep feeling not as run down.
Have a good trip!