Post list of things to do on the plane w/2yr old.

[SnowWhitee]

In addition to what has been mentioned, here are some others we've used:

Play-doh and cookie cutters
Crayola fingerpaint - this only colors on their special fingerpaint paper, so no mess!
Magnets to arrange - Colorforms or something similar with a foldout board or tin
Puzzle - choose one small enough to fit on the tray once assembled
Stamps and paper - you could buy the self-inking ones