Having been there, done that (not having had one single totally pain free day since April of 1983), I can say with all sincerity that I feel your pain. I too eat 800mg motrin like candy. Got several super duper muscle relaxants, but I have found that rum and/or vodka does just as well, and tastes better. One thing you might try is stretching exercises. Lay on your back and bring both knees up to your chest (like doing a cannonball into the pool). Hold for a while, stretch out, repeat half a dozen or so times). Then do one leg at a time, same thing. There are more, but it would take me forever to describe them. If you go visit a licensed physical massage therapist he/she can show you all. Good luck, and I do not envy you your time inflight. I hope you get a front row seat in first class, at least that way you can stretch out...