> as my understanding is they don't have pilots fly too often
From a quick search, I can’t find evidence of this. If anything, pilots are in the air more of their week/lives vs. flight attendants.
I guess I am going off when a pilot spoke at my high school for career day. (Decades ago...)
In my search, I found that they spend almost an equal number of hours in air like you said - 75-100 hours per month. If that's the case, after adjusting for sex, these numbers holding would throw some uncertainty into the radiation hypothesis.