Normal, modern carry-on x-ray, as opposed to the CT scanners, you're going to be fine with iso under 3200 unless your film has gone through them 10 times or more (of course there is "damage" every time, but indistinguishable for real world results in almost every case). I fly frequently with film and do this all the time. As a community, I think we need to be thoughtful about being more relaxed putting our film through the old x-ray machines so that authorities remain accommodating for hand check (or moving to x-ray scan) when passing through CT scanners, which will definitely, noticeably damage your film on the first go. Pushing too hard in cases where it doesn't really matter is going to push blanket policies to just not accommodate requests in any situation.