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.
I rarely sleep longer than 90 minutes at a time, unless I’m physically exhausted already. And yes, the neck hurts, but exhaustion hurts more.