I'm a lowly student on my way to an NPPL(m), but my job is automation of software testing processes.
I always sell automation to my clients in the same way: It will save money by taking on the bulky repetitive tasks (like regression testing) but there will always be an element of manual intervention required. Humans will spot things the automated code won't; but it's not good at performing highly complex tasks that require intuition, and cannot perform exploratory testing.
Automation tools are often sold on the promise that they will catch everything, and it is true that, in some rare cases, defect detection rates may well be better than when the testing is executed manually. But true AI does not exist as far as I know - and even if processing power ever reaches that point - I still firmly believe the human element can't ever be eliminated. We are simply far better at picking the important stuff out of the data we're bombarded with, we're better able to recognise patterns, and we can act upon those cues subconsciously.
Granted, sometimes the humans make incorrect decisions. But we are adaptable and often able to self-correct in time to avoid disaster.
I don't think we'll see pilotless passenger aircraft anytime soon. And I'd certainly never step foot on an aircraft without a human flight crew.