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.
Before: Turtl Travel Pillow. It’s not easy, but it helps.
Now: Business class. I fly enough to rack up enough air miles that a seat upgrade is affordable if not free.