Most of nmy friends check their infant/toddler carseats. We are bringing it on board and I am looking for input. Flying American Airlines on an international flight, with a large Britax seat. I'm aware it will cramp us sitting next to her. I'm not positive it will fit unless the arm rests go up. I've heard it depends on the airline. Thanks for any input. P.S. we plan to use the Britax travel cart for ease of airport transport. Any other toddler traveling tips welcome:). We have a bunch of new toys stocked for the trip.