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.
The noise of the engines tends to help me. Same with sleeping on a long car journey. They hum or white noise or whatever of the engine and the road really help. Also why I like to sleep with a fan on. Not only to help cool down. But also because the noise really gets me to fall asleep sooner.
That’s what I do. I purposely pick seats nearest the engines
I have flown a hundred times and slept exactly once. It was like teleporting from Osaka to Sydney. If I could do that more, it would be very good.