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.
Pure exhaustion from all the “hurry up and wait” of airport bullshit.
By the time I’ve gotten out of bed, gotten ready, travelled to the airport, dragged all my shit through the airport, unpacked and repacked half of it through security, boarded the plane … my body just kinda gives up on being awake.