My daughter took 16 flights before she was 1. First flight at 41 days. She's at 34 flights now, at 18 months. These are long haul flights for the most part, average flight distance is 2,515mi.
She's traveled well on pretty much every single flight.
Those who haven't traveled well have been quite a few of our neighbors.
When the cabin is dark,
a) shut up
b) turn down the brightness on your screen to minimum, or better, turn it off
c) shut up
d) definitely turn off your screen if you're going to sleep FFS
e) shut up
Incredible the amount of people who lack basic decency.
The worst travelers were a group of Mexican couples on a flight from MEX to PVG with a brief touchdown in TIJ, who would not shut up the entire flight. And then had the gall to complain that our daughter was crying because they wouldn't let her (or anyone else) sleep. It was pretty apparent that this was their first time on a plane, but still, some things should be pretty obvious. Especially when we asked them multiple times to be more considerate.
But apart from that one flight, she usually sleeps through most of the flight, and plays/reads/eats fairly quietly during her awake time. Oh, and walks around the aisles making friends with the cabin crew :)