As I am someone who has a hard time sitting still for any length of time, when I travel on a plane, I get restless. Three hours on a plane without the ability to move around, explore and be free? I know, it is only a short amount of time, but when you add up the hours spent traveling to the airport, waiting in line for security and then waiting at the gate for your flight to be called, it amounts to far longer than just flight time. As I sit at the gate, I people watch. I see most people chatting on their phones. (And while I can understand their feelings of frustration at being trapped, I can't tell you how I DON"T WANT TO HEAR their personal calls -- or their professional ones for that matter.)
As I wait at the gate, I will read a book or magazine, but once I board the plane and we finish take off, I take out my art journal and get to work. Sometimes, I do other art stuff, but I try to look at this like 3 hours of uninterrupted art time.
Here is my latest watercolor art journal that I used on my last flight.
I can usually get 3 images done on a three hour flight. Sometimes more, sometimes less.
But for the the most part, it helps me take my mind off being confined and allows me to be focused and busy for the flight.