Flying makes sense to me. The bottom 30k feet of the troposphere blocks a lot more potentially carcinogenic radiation than the aluminum skin of an airplane does, and the top 10% of all commercial flyers put in a /lot/ more hours in the stratosphere than the vast majority of the population.
Assuming it's a genuine effect, it could be due to other factors: for example nightshift work is associated with reduced lifespan and increased cancer rates, apparently because of disrupted circadian rhythms - and flying across timezones is pretty darn disruptive too.
7 Random Things You Won't Believe Are Shortening Your Life
TL;DR
1. Starting School Early
2. Being the Eldest Child
3. Having a Small Ass
4. Flying Often
5. Living Closer to Sea-Level
6. Not Going to Church.
7. Retiring Early.
I'm glad a high-traffic site such like Cracked is giving some exposure to the issue. Can anyone here comment on the reliability of their sources?