The least a parent could do is take the baby out of that car seat for part of the flight and have some time in arms and with a change of position. (phdinparenting.com)
There are many types of car seats out there, and some of them convert from one type to another. (babycenter.com)
Try and research online to find out which brands of car seat stroller combo offer things such as impact protection and distribution of crash force. (bestbabystrollerjudge.com)