I spent time last week at a meeting discussing the use of drones to deliver cargo in very specific circumstances as a very specific piece of very specific supply chains. It made me rethink the '
remove the pilot from the flight deck to remove pilot error' argument which is occasionally raised here to be ritually shot-down.
I have to say I was really impressed by the progress. I saw demos of (ADSB-equipped) drones flying purely autonomously, right under the approach path of a small regional airport, and delivering up to 5Kg over ranges of 50Km or so. They were discussing the idea of exploiting the lower airspace (<500' AGL) for high value and urgent items - critical spare parts, critical medicines etc. My very strong suspicion is that this will become established over the next 5 years and in the next 10 years, a lower airspace full of autonomous drones zipping around will be part of the aviation world.
I think that is a world away from pilotless long range passenger aircraft, but the gap is closing in cargo. I saw a description of an autonomous drone with a 1,800Kg load and a range of 1,000s of Km (
FLYOX singularAircraft), that could replace a Twin Otter or a Caravan.