Time! Time is a sketcher’s greatest ally. Time was what abounded in the plane trip back home for a few weeks of holidays.
Apart from the short bursts of slight turbulence and the lacking of depth in one’s perspective (which usually accounts for the fish-eye sketches), I’d say a plane is one of the few places where you don’t get much distraction from your sketching activity.
One other place being the very airport where said plane lands. Themes are as varied as can be – cars, modular buildings, coffee cups, assorted machinery and tarmac bric-à-brac, hostesses and passengers and a plane with the old Lufthansa logo and paint job being towed.