Can you rent a car seat where you are going? Maybe you should check into that possibility. I've known friends/family to do that before. I'll have to find out where they rented them, though, if something like that would help you out.

Otherwise there are strollers that have the car seat built right into them. You can use it as a stroller OR a car seat with a few minor adjustments.

When I traveled (14-16 years ago) with my son when he was a baby, we just checked the car seat and the stroller both with the luggage. They didn't have any problem doing it that way.

Let me know if you would like me to look into this rental car seat idea. I know it's been done around here before......