How old do you have to be in order to check-in by yourself? My son who will be attending the US Air Force Academy will be getting Christmas break before our other children's schools let out. We are trying to plan where he can fly out of Colorado Springs and go to Disney for the week prior to our arrival at Disney for Christmas. This would give him a little time to completely relax from all his hardwork and be at a place he truly loves. I know it will be extremely busy. Just trying to figure out if an 18 year old can check in - the reservation would be compeletly paid for.