R.B.
My son is almost 3 but has been flying since 3 months. Best advise i can give, schedule the flight during her naptime or an hour after her naptime.
The "plane noise" seemed to be soothing to him as well and to my surprise everyone on the plane said "i didnt even know there was a baby on the plane". AND keep in mind, the more anxious you get about the trip, the more she senses that and the more SHE acts up. Just be very calm, bring some new books, some good snacks and maybe even a portable DVD player with a new movie that doesnt get opened until the trip!! I never travel with out it these days and it's been the best investment. Best of luck and have a fantastic trip!!