We are flying down in May and can't get a straight answer on whether we need carseats or not on the plane. We are travelling with our two daughters, ages 2 1/2 and 3 1/2. According to the airport website our oldest doesn't need a carseat and youngest does. However, the fact that she still uses one in the car makes me think that she should have it on the plane. I also had a local police officer tell me that the FAA requires any child under 40 lbs to use it on the plane. Anyone have any experience with this? Thanks for any help in advice.