My wife and I will be flying to Miami next month to cruise on the Magic with our 3yo son. This is our first time flying with him and we are a bit nervous. He will have his own seat, he might just be turning 3 but he’s the size of a 4yo, but we are concerned he will wiggle out of the seat belt. My wife wants to buy a booster seat for the airplane but we are not sure if that is allowed. Anyone have a experience with this?