sleeping sitting up

I was on the plane when I wrote this --

I'm on the plane now. It only took me 10hours to find the powerpoint to plug the laptop in. I just woke up actually. They dimmed the lights at about 2am. I woke up from a dark and silent dream where the plane was shaking and the oxygen masks had just started dropping from the ceiling... Woke up in a fully lit cabin by an air hostess' gentle tap on the shoulder, mouthing words I couldn't hear. Ear plugs. Would I like breakfast? 10 second pause while I remember who and where I am. Yes please. I just slept for 8 hours! Sitting up! How did I even do that??