It's often said that we receive just as about as much radiation exposure flying than we do getting a low-dose chest X-Ray (see this page; this page; or this page). Apparently we get about 0.05 mSv per seven-hour flight (a chest x-ray is 0.04mSv). What does this mean for our film? Perhaps we shouldn't be as worried about the carry-on X-ray machines as much as background cosmic radiation. High-energy radiation can also flip bits in flash memory cards, so you digital photographers aren't as safe as you think you are.
This entry was originally inspired by Dean Armstrong, who blogs about his experiments with a cheap geiger counter:
I bought a Geiger counter as a birthday present for myself. It is an Aware Electronics RM-70. It is cheaper than traditional Geiger counters because it is designed to work with a computer..... [I used it on a] Southwest Airlines flight to LAX. I turned on the detector at roughly 12,000ft, and turned it off at the official 10,000ft announcement. According to the pilot cruising altitude was at 39,000ft. The big drop at 3/4 of the way across the graph was a temporary disconnection.
Comments on radiation, flying, and film are more than welcome.