Tiffany Towncar does, we've used them multiple times. Always good service, they come early/on time, include a trip to the grocery store on the way to Disney and the booster seat we'd get was always clean. We always got a booster seat though, never a rear facing car seat for a small infant. I know they do offer "car seats" but I don't know what kind it is or how old they are... I'd probably bring my own in my kid was still a baby. Bring it with you to gate check it but then ask the terminal agent if the plane has any extra seats near you, maybe they would let you just have it for the baby and you could put the car seat in it with the baby in it. When we took our son to Hawaii when he was a baby and I took his car seat, that's what I did. One leg we got the extra seat and he had his own seat with the car seat, one leg we gate checked it and I kept him on my lap.