My daughter loved playing with tape at that age -- I would stick short pieces to her fingers and she would be fascinated with how it kept sticking to her (I'd remove it, of course, if she got frustrated or started to put it in her mouth). I kept a roll of masking tape in my purse for this purpose, it worked at the grocery store too! She also liked paper that had been crumpled slightly. She'd wave it around and tear it and generally have a blast with it. Small bottles of bubbles, like the ones for party favors, were also great. The plane trip itself will be pretty exciting for her, too, especially if you spend a lot of time talking about what's going on and what you see out the window and that kind of thing. And I always made sure to nurse during takeoff and landing to help keep my daughter's poor little ears from getting too pressurized!