X-ray does not actually kill film. It will just slightly increase the esposure. But on the films I took through X-Ray scanners I never noticed this. Also you can take the film with you in your carry-on and ask the person at the scanner to let your film pass unscanned. Worked for me back when I was concerned about this. :-)
Oh and film also doesn't die after its expiry date, I made enlargements of some shots from ten-year-past-expiry film recently, not technically perfect but I love the look. Try a roll and see what you get!
I've never had any trouble getting film manually inspected, in recent times, in many countries. It seems routine to the screeners, which surprises me every time.
X-rays definitely do fog film though. If you care enough to use film, but not enough to ask someone to manually inspect it... that's weird to me.
I was able to avoid X-ray exposure to all of my film (some of which was ISO 1600 that I was pushing to 3200) during a trip to Washington D.C. not long after the 9/11 attacks. At that time, all of the security checkpoints at the airports, monuments, etc. seemed to be on edge. However, by politely requesting hand checks of my camera and film I was always accommodated and never had my equipment X-rayed. Checkpoints that had swab based explosive scanners always utilized them during the manual checks.
I was worried about the lower ISO film as well because going to ten different museums/monuments a day meant ten security checkpoints. I didn't want X-ray exposures to accumulate for even the low ISO film.
That depends on the sensitivity of the film and the strength of the X-ray imager.
100 ISO through carry on once? Probably no issue. Instead of once, 8x? You'll see things. ISO 1600 through carry on once - you'll see lines. 100 on checked luggage? It's gone.
Oh and film also doesn't die after its expiry date, I made enlargements of some shots from ten-year-past-expiry film recently, not technically perfect but I love the look. Try a roll and see what you get!