This is usually a misunderstanding of risk. I think the last stats I read were that per 18,000,000 miles of air travel for 200 people, you'd expect 1 extra pers

This is usually a misunderstanding of risk. I think the last stats I read were that per 18,000,000 miles of air travel for 200 people, you'd expect 1 extra person to end up with cancer. Over a baseline risk of 25% of people getting cancer, that's negligible.