How to Fly with Film
UPDATE 5/4/2014: Recent findings and friends' experience suggest that modern airport scanners (often no longer even referred to as "x-rays") do not harm photographic film of any type or speed. While I cannot find confirmation of this, it seems to be clear in the experience of other film photographers who tell me that their film was scanned against their wishes multiple times on trips with no ill effect to their images.
That said, I don't think that it's safe to just assume that this is the case so in the meantime, I recommend the following the conventional advice below whenever possible.
I've flown all over the country with film. While folks, including myself, have had issues with security outside the United States, TSA staff within the States are very film friendly by and large.
The absolute best thing to do is buy and process film locally but this is not always an option if you are not familiar with the area where you may or may not be able to buy the film and get the trusted, quality processing you need. So below are my top tips for flying with film.
--Take all your 35mm film out of the plastic canisters it comes in and your 120 out of the wrappers and place all of it in one clear plastic Ziploc bag. As you should be keeping your camera with you for carry-on, keep this bag with you. The goal is to keep the contents of this bag easy for security to see and riffle through quickly even though it kills any chance of maintaining good organization!
--Just as you're getting up to the security gate and have all your other carry-on items in the bin, hold up your bag of film and ask security for a hand check. Someone will take your bag around the scanners and meet you on the other side after you and your carry-on items have passed.
--TSA will rub a bit of explosive-tracing material on the leaders of each roll of 35mm film. If you bring a lot of film, like I do (20-50 rolls depending on the trip), this can take a while so arrive at the gate early! They seem to simply visually examine 120. Taking the film out of the canisters and/or wrappers speeds up this process and usually they will let you start bagging your film back up as they finish each roll. Most guys I've dealt with are very friendly and ask me where I'm going and what I'm shooting etc.
--800 and slower ISO's are not supposed to be affected by X-rays but X-ray damage to film is cumulative so it's best to just get a hand check everything regardless of ISO and not worry about it. However, I've seen 400 ISO film go through 3 X-ray scans with absolutely no affect to the film.
--DO NOT put your film in checked baggage as it's sure to be X-rayed. (this advice still holds true as x-rays, not modern scanners, may still be in use for checked baggage)
--You can buy a lead bag to put your film in to protect it from X-rays but I've always heard that this will just cause suspicion so I've never tried it as it doesn't seem to be worth the additional cost if that's the case!
The airline doesn't make any difference. The brand of film doesn't make any difference. The main thing is the ISO and how many times it gets hit. Supposedly, though I've never had to deal with it, 800 and faster films can be damaged by just one scan.
Anyone who says x-rays are a good reason to go digital doesn't know what they're talking about. Making creative and/or archival decisions over matters of convenience alone makes no sense. Often when traveling with film, I meet other photographers and have great conversations with them simply because they see I'm shooting film.
Good luck, take some great photos and enjoy your trip!