A.C.
i took my daughter when she was 4 and I had no problems. Make sure you take snacks on the plane, try to get her to eat them while taking off and landing and you should have o problem. About the booster,they don't need it on the plane but I do suggest taking it. I would check it with the bags. We didn't take one and they did not have any more at the car rental and we had to purchase one from wal-mart. The ones that I have seen are pretty dirty as well, so you are better off taking your own. Also make sure you take a stroller, it is a very big place and they get tired.