Hey, I think it's usefull to know that they use two kinds of x-ray machines. Checked-in luggage is checked with pretty heavy radiation levels, so all your film that you leave in your checked in luggage will be completely gone. BUT if you take your undeveloped film onto a plane yourself, it's as good as impossible that it'll be influenced by the x-ray machines that you'll pass yourself. The machines they use nowadays are very low on radiation (mostly to protect the people who work with those machines all the time).....you can take a chance on that at every normal airport. However, in a lot of poor countries they still use older machines that might damage film - but even with those, it's still a small risc. Another exception is film like high speed IR, which can't handle any radiation. So next time, if you want to be sure, buy a photobag from LowePro, which has a protective bag for film. At the airport ask them if they can handcheck that small bag (you can take it out of the main bag easily), and throw the main bag into the x-ray machine.