It certainly appears to be an intractable problem to me. Gotta have someone on the airplane to control it for reasons of potential jamming/interference/etc. Person on plane must be able to override any external guidance for similar reasons. Can't have one person riding around who can crash the airplane unopposed (remember the old joke about the pilot and the dog...). Therefore two pilots until perhaps onboard AI, and I don't think that's exactly right over the horzion.

I am also no expert.