Sometimes – quite frequently, actually – I fin myself on an aircraft with not very much to do. I fly often enough and spend enough time in the air that I’m one of those people who will bother to try and find out the flight route in advance and pick the seat most conducive to photography on arrival or departure – assuming of course there isn’t an engine or wing in the way*. I’ve gotten some very satisfying images this way.
*Frequent travelers will know there’s always a tradeoff: the front of economy is usually blocked; the rear usually is noisy and has a lot of traffic en-route to galleys and toilets, and the view isn’t always clear because of the convection visible due to the engine exhaust heat. Or, you fly up front and land up bankrupt.