YOur car seat should fit in all classes of US flights. Some Euro flights have a bassinet and don't allow car seats. But if you are flying into/out of US, I think they have to follow us rules. There is a seat that FAs made (you can find it on their site and others) which works on all and is east to carry. Does not work in cars i don't think Also, if you have an infant (rear facing) some FA have said no to their usage. bring law with you All us plane must allow