I can fall asleep almost anywhere. I routinely fall asleep in the break room at work. Once, I was helping a friend fix his car, and I fell asleep on his garage floor when he went inside to get water.
But in a hot metal tube tearing through the sky, with my neck all kinked? Get out of here, man.
Alcohol and Benadryl. Its worth noting that I never feel like I’ve slept. To me it feels like I am just hovering on the edge of sleep the entire time, but my wife says I do sleep for a solid hour or two at a time.