Thanks for doing this experiment for us. It demonstrates that CT scanners can do real damage, though I am equally sure people sometimes get lucky.
Thankfully we're now getting a lot of data from real life situations where people are able to get film hand inspected at airports around the world. This certainly won't stop me travelling with film.
I fly a lot for work (including outside the U.S.) and almost always carry a film camera with me. I can offer a few tips based on my experiences, especially ones I've had over the last 3-4 years since CT scanners started becoming more common at airports:
1) (Most people probably already know this one, but...) Don't put film in your checked baggage. Checked baggage screening typically utilizes either higher-intensity X-ray machines (compared to the X-ray machines used for carryon-on screening) or CT scanners, both of which can do observable damage to film.
2) (Most people probably already know this too, but...) Remove any film from your camera before going through passenger screening at the airport (i.e., where they check you and your carryon items). Security personnel, in most cases, will not be willing to do a hand-inspection of a camera, especially an electronic one, which means that any film still loaded in it will have to go through the scanner along with the camera. That's usually not a big deal if it's an X-ray machine but can be a problem if it's a CT scanner.
3) Put your carryon film in a clear, Ziplock-style bag (as opposed to something like a lead-lined Domke film bag). If the security worker you ask for a hand-check from can immediately see what's in the bag, they'll be much more willing to agree to the request. Those lead-lined Domke film bags are nice for storing film (i.e., they're dark inside and have a Velcro enclosure) but they're basically useless now for air travel purposes. They offer minimal protection against CT scans and aren't needed in most cases for X-ray machines, as most people aren't using film that's higher than ISO 800.
4) Regarding Domke bags specifically: If you do choose to use one for transporting film through the airport, don't send it through a CT scanner; ask for a hand check instead. It won't offer much (if any) protection against CT scanning and it'll almost always trigger a secondary screening request by the scanner operator, which means the film will get pulled out and hand-inspected anyway. With an X-ray machine, you
can safely send a Domke bag through it (that's what these bags were made for), but be aware that doing so will similarly trigger a secondary screening request due to its opacity to X-rays. Domke bags are nice for film storage when you get to where you're going, so I'd suggest packing it (empty) in your checked luggage and packing your film in a Ziplock bag while moving through airports.
5) Learn to recognize the difference between an X-ray machine and a CT scanner. An X-ray machine generally has a square or rectangular profile and will look older (often with an aluminum or stainless steel exterior), while a CT scanner
generally has a round or oval profile (though, I have seen rectangular ones) and will look new (they often have a white or beige-colored plastic exterior). CT scanners are more likely to be found in international airports in North America, Western Europe, and Eastern Asia (e.g., Japan, South Korea, China). Regional airports in the U.S. and international airports in less-developed nations are more likely to still be using X-ray machines. If you're approaching the security area and are confident you see an X-ray machine, you needn't bother asking for a hand check (unless you're using high-speed film, I suppose).
6) Be polite and direct, and speak clearly: "Excuse me sir/ma'am: Could I have a hand-check for
some photographic film?" Hold the bag up as you ask the question so he or she can see exactly what you're referring to. If you merely ask the question without displaying the bag, they might mis-hear you and/or be confused about what you're asking, which just increases the chance that they'll deny the request. Confusion almost always leads to suspicion and annoyance, so use words and a visual aid to leave no doubt in their mind about what it is you're asking.
I travel frequently through Denver, Houston, Chicago, Newark, Frankfurt, and London and have never been denied a hand check. I also travel a lot though the Middle East (Kuwait, Oman, UAE, Saudi Arabia) and have yet to see a CT scanner at their airports. There are sometimes differences between the screening technology being used in one part of an airport versus another (e.g., security checkpoints for passengers going landside -> airside, versus security checkpoints for passengers transiting airside only), but if you stick to the above guidelines, you'll likely breeze through without a problem.
Bottom line: Make it easy on yourself. Only ask for hand-check when you see a CT scanner. If it's an X-ray machine, just send the film through and don't give it a second thought.