Laying your head over your tray table helps with nausea on turbulent flights.
I have a great tubular squishy pillow that I can use as a head support when leaning over my tray table on a flight. I put a regular airline pillow between it and the tray table so that I have something to rest my elbows on as I wrap my arms around the squishy pillow to make it firm enough to support my head. I have actually fallen asleep a few times doing that right after being nauseated trying to sit normally. Something about turning my head that way really helps with nausea.
