The airlines have some "baggage" from 60's, 70's, 80's, and 90's...

Back in the day, they inadvertently hired some pilots who had flown drugs for a living in the past (I suspect a few are still employed today).

So they are VERY anal about accounting for ALL periods of alleged "unemployment". They want to know for sure that you didn't do anything shady, ever, in aviation or otherwise. If they can't satisfy themselves with reference checks, they might want to see W2's, tax returns, etc. Majors more so than regionals.

Very annoying for career military people, you end up trying to account for every 30 day TAD, school, etc.

Hopefully your construction days were W-2 or 1099.