I have a few non-drug strategies:
1) Don’t drink the coffee on the plane, and you’ll sleep better (the caffeine keeps you awake). But they constantly offer it.
2) Buy a pair of noise-reducing headphones. You’ll sleep better. Get the over-the-ear not the in-the-ear type.
3) Try and get to your destination early in the morning if you possibly ca. (say, 10am).
4) Don’t sleep until you absolutely must (say, 9pm) once there.
5) Try and eat at the normal times, even if you are not hungry.
6) I go for a job or something if I can when I feel like sleeping. It stops me sleeping for a few more hours.
7) If you can’t get to sleep, I could point out the obvious guy solution