There have been a couple threads on this in recent months with different suggestions, and certainly many opinions on prescription items such as Ambien, Sonata, etc. For shorter flights my doctor recommended 1-2 Benadryl. (I'm able to sleep like a log on any flight as long as it's not a redeye...go figure.) My last few redeyes I've taken 2 Benadryl (one didn't do much for me) and gotten a solid 5 hours of sleep each time which was perfect for the timing of those flights after meal service, etc. Hope that helps... As with everything else, YMMV and definitely try it out at home before you travel.