How often can you fly on a plane before suffering effects from space radiation?

A lot: There are guidelines for total radiation exposure associated with commercial flights. A typical airplane flight will expose a person to roughly 1 millirem per hour of radiation. Guidelines from the international commission on radiological protection (icrp) recommend less than 2, 000 millirems per year of exposure. That would mean 2, 000 hours of flying per year before concern would arise.

Not concern for most: Other than professional pilots and flight attendants who fly for a living, the average traveler who flies receives so little additional radiation that it is still within safe guidelines. You would need to fly for 8 hours every other day to accumulate significant additional radiation exposure. Remember that non-fliers are exposed to radiation daily.