Traveling is not only about filling your film stocks in advance and finding the proper lab that won’t damage your films. It is also about keeping the films safe until the moment they will be proceeded for development.
Some say that any film speed below 800 ISO is safe from X-Rays, others add that it should be done no more then 5 times. In most countries the X-Rays baggage checkers are tuned to nearly 1/3 of their power. It might be safe. However, even there security staff are allowed to put the power up to its maximum in case of uncertainty and for the safety reasons, something that, as you can imagine, is not that good for your emulsions.
Most of time I’ve tried to keep the films in the specialized X-Rays safe bag (available in most Photographic stores). But if you feel like a little bit of DIY you can always modify a bag that you already have (all you need is to add 3 layers of foil!) I’ve also tried not to forget to pull out from my bags the cameras and the films that were just extracted from the camera or those that I was intended to push into the camera. Unfortunately you can still see some traces of the X-ray on my photos as I tried to put 80 films inside a bag made for 30…
Something somewhere still got a chance to go slightly wrong. Here is a proof: in spite of all the precautions some of the films succeeded to catch some radiation. Enjoy the pure analogue artwork on Ilford Pan 400 ISO or Kodak 160VC and beware of the “film safe” stickers :)