travelling long haul with my 4 year old, i find that a toy drum set and accompanying toy working microphone keep her occupied for hours and also lightens the mood in a packed economy cabin - i also like to stick a target on the seat back infront of her where she can practice landing hard kicks
but seriously my child is a well behaved traveller and i find that a travel sized doodle pro is great and i we carry her leapfrog with a couple of new games, tag reader with new books and spare batteries ar. she has her own head phones so the sounds dont disturb others. this time around we also have a fisher price camera for her - she can click away @ the airport during the layover. she also enyoys activity and sticker books so we always buy a couple of new ones with her favourite characaters (dora, etc.) for her before travelling
needless to say all of the above keep her occupied for an hour - 90 minutes tops - after which i quickly request for a few rum n cokes and resort to the drum / target combination so she can keep herself oocupied for the remaining part of the flight