Something not mentioned in the article is the type of radiation you get on a plane.
At altitude you can get very high energy neutrons, mesons, xrays, gammas, cosmic ray secondaries, and the interactions of all these things with the plane.
Not exactly the bremsstrahlung you get from an xray tube.
bremsstrahlung sounds like some kind of bizarre German sex act.
Fortunately for many airline pilots they will spend several years on the bench at least once in their career on furlough.