I think GP's point is more relevant than your question implies. The vast majority of civilian flights could be flown entirely autonomously right now. (I'm not close enough to the aviation industry to make a confident guess, but +90% wouldn't surprise me.) Humans are there to take (decision or control) over when something goes off the happy path - in fact, pilots are encouraged / required to hand-fly landings that could be done automatically in order to keep their skills current. Obviously no one would accept even a 0.01% crash rate for civilian flights, so we're many orders of magnitude of improvement away from replacing pilots in that sector.

Military calculations are very different. Every military asset - most definitely including humans - is disposable, and all wars are (in some dimension) wars of attrition. Holding mission success constant, when the cost x capability x ability to manufacture for autonomous platforms becomes cheaper than all that plus training / replacement cost of human pilots, then human pilots will disappear. The logic of war being what it is, I expect HITL decision-making to very quickly be dropped as soon as it is seen to be retarding the progress of a cheaper option.