I contacted a rental car center (dollar rental I think) and she told me five year olds don't need to be in a car seat. My son is only 42 lbs and I don't think that's right. Anyway, we are flying contintental and was wondering if you can take a car seat on board and use it for a five year old. Their website didn't have a lot of information about children only infants and customer service didn't really know. And the email I sent them has yet to be answered. Thanks