I think we can trust them to not have human pilots. It is just that having human in loop is very useful in not that rare scenarios. Say airfield has too much wind or fog or another plane has crashed on all runways... Someone needs to make decision what to do next. Or when there is some system failure not thought about.
And well if they are there they might as well fly for practise.
And no. I would not allow LLM in to the loop of making any decision involving actual flying part.
There's also the issue that when something goes wrong, many people will never trust an autopilot again. Just look at how people have reacted to a Waymo running over a cat in a scenario where most humans would have made the same error. There's now many people calling for self-driving cars to never be allowed on roads and citing that one incident.