As a poster who's only qualification is being a parent, I wanted to add my 2 cents. I have never flown w/out my carseats getting slight to moderate damage. The airlines care not for your seats, and will treat them as such.
Carry them on whenever possible. If checking, try to check them at the counter, in safe wrapping. If you have to gate check them, put them in some sort of secure bag. And I did finally resort to buying bottom-of-the-line-but-still-very-safe
Graco seats, to save damage to my $$$ Britaxes, and because Britaxes are so darn heavy! The kids are fine in those, though by the end of the vacation they are happy to get back to "their big blue seats!"
Hope that helps, and if not, please disregard. Safe travels!
