We did also take flash cards with the little machine to put in and say the word but they ended up flying all over the floor, but could always do a diy flash card set on a key ring, numbers, letters, colours, animals. ( then could always go back to it throughout the flight)
Putty from Asda/ B&m or Amazon. Stickers, water pen colouring book(mess free) fidget spinners, Busy board book. Books.