Honestly, traveling with film is kind of foolish ...
Think about it, you are purposefully adding additional tasks and anxiety to the security check; security checks are already terrible for most. Whether you are at friendly airport or at a very unfriendly airport, there is always a very real risk that your film will end up going through a X-ray scanner.
You can check out this video to hear some of my thoughts or just continue on and read below.
How to mitigate the risks
There are a few things you can do to mitigate the supposed risks of x-rays
Avoiding x-rays
pack your film in large clear plastic zip lock bags
remove as much packaging as possible from all film
be very POLITE and CONFIDENT in asking for a hand check
if possible, lie and say your film is ISO 800 or higher (many airports only hand check 800 or above)
try your best to avoid bringing large format film or bulk rolls - high risk of being mishandled / exposed to light
do not leave any film in your camera - cameras will not be hand checked
look out for CT scanners - these are reportedly bad for ALL film
Minimizing impact of x-rays
lower ISO film apparently poses much lower risks
comply with all security instructions to avoid multiple runs through an x-ray machine
do not travel with higher ISO film -- many have documented problems after x-rays
buy/develop your film at your destination - negatives are 100% safe for exposure to x-rays
Using a lead Bag
Some say using a lead bag is the answer. In reality it isn't. Yes, the lead bag will literally protect your film from x-rays. However, after it is seen by the security person using the x-ray monitor, they will either a) hand check the contents (this is good) or b) they will empty the contents onto a tray and then force the contents through the x-ray machine (this could be bad). Get a lead bag if it makes you feel better but be aware that this doesn't guarantee anything.
Don't be mad if no one cares ...
In the end there is no full proof way to guarantee a hand check for you film. Perhaps if you fly in a private jet, the security will be more amenable to your requests. Many airports around the world, especially in countries where the film resurgence is minimal, will not care at all for your request. Even in England (the home of Ilford!!), at Heathrow Airport for example, they will only hand check film above ISO 800. If you decide to travel with film despite the risks, that is 100% on you and no one else.
With that said, I still travel with film and even get mad when it doesn't go my way 😂. So far, none of my film has been noticeably affected by countless encounters with x-rays. Good luck! - Ribsy