Pentagon refused delivery of so many F-35s Lockheed running short on storage
defenseone.com
defenseone.com
The only aircraft I know of that was assembled on a moving "line" was the 777. It was a major innovation with that aircraft but not duplicated. Still it wasn't an assembly line in the sense of an automotive assembly line. Rather the aircraft were rolled along through the building very slowly as they were assembled.
The DoD exists first to feed MIC pork projects and maximize the number of subcontractors, and "defense" second.
Recall that the iPhone would cost over a billion dollars if they only made 100 of them.