I check people out in the boarding area and when they're boarding and getting seated. After we're strapped in and cruising for takeoff, I'm out within a few minutes. I was the kid who loved to set on the backseat, with my head on my Grandma's lap and sleep all the way home from the beach. I'm an Olympic sleep team member .. LOL.
I am fully alert the whole time. I think I have slept a couple of times... but I must have been terribly tired or bored. You are blessed.