Earlier quoted context omitted.
> How many airplanes crashed due to The pilot being on drugs? As long as testing is uncommon you could say that number will remain at zero or near zero simply for lack of data. You comment implies but doesn’t state explicitly that you think truck drivers are more likely than pilots to be on drugs, is that true though?
Based on likely social setting difference due to salary difference plus the fact that truck drivers go through seedy places and do many long stretches alone, compared to pilots frequenting airports and hotels, and always working with a crew, I'm sure truck drivers use more drugs than airplane pilots. If you are not sure of this, I think your mind is "too open".
“To a degree” means some pilots will still stay up late and try to use stimulants to stay awake. But the pressure on the two cohorts is not equivalent.