Cramped seats aside, the thing that made long flights a lot more tolerable for me is getting (muscle)relaxing medicine (something like Xanax) prescribed by my d

Cramped seats aside, the thing that made long flights a lot more tolerable for me is getting (muscle)relaxing medicine (something like Xanax) prescribed by my doctor. It calms me down and if I take a bit more I can sleep wonderfully and eradicate jet lag. Obviously, 20h is a bit extreme but it helps me forcing myself into the sleep rhythm that I should be in.