What can I take to help me sleep through a flight?

I've been asking friends and family, but didn't think til now to ask here!

Tonight, I'm taking a 5-hour red eye flight from Seattle to Philadelphia. It's going to be around the time I usually go to sleep, 10:30pm.
Last time I was on an airplane, however, there was some major turbulance, and the plane turned itself sideways at an almost dangerous angle. Understandably, since then, I've been a little nervous about flying again.
I know statistically there's almost no chance of anything happening...but I'd be much happier if I could sleep through the entire thing.
(As a note, even when sleeping in my own bed, I usually tend to wake up a couple times during the night.)

I've been suggested Excedrin PM, Nyquil, and taking a couple shots.

Does anyone have any tried and true methods?
I need to be able to wake up after 5 hours, too, to get off the plane and make my connecting flight. I am travelling with my fiance, so if it's necessary that I be woken up, he can do that.

Thank you so much in advance for your help!
Additional Details
I have allergies and take antihistamines regularly, so benadryl is pretty much a sugar pill to me. ;)