Could you Bf to sleep? Books with moving parts are fun, little clear bottles of water with things floating in them (not sure if they'd let you have it on the plane though), interesting things threaded on a strong cord, I wouldn't worry too much about a little noise - I'm sure everyone would prefer that to a crying, upset baby! Can you ask for a seat near an exit so there's room on the floor for her to play a little? Good luck!