That could be correct. Most people don’t realize there is radiation exposure associated with flying.
Flying in mid-latitudes over 23K feet can give you about .3 mR/hour in non-flare conditions. During a solar flare it goes up, and it goes up with altitude and latitude. In most places, the normal ground level background is 20 micro-R, so 300 uR is significant.
Above 34K feet, there are loads of neutrons, and some mesons too, from cosmic ray primary collisions. Now that memory cells and processor cells are so small, there is work being done to investigate “neutron single-event upset”, where high altitude neutrons mes up the function of some electronics.
In the EU, pilots and attendants are considered to be radiation workers and are given dosimeter badges.
And we are told that it’s the baggage x-ray that ruins your film you shot in Paris, then flew home on a polar route!