Shortly after the introduction of secure doors, there was an incident on an Air Afrique or Air Mali plane, the Embraer flying from Bamako to Nouakchott. The pilot went back into the cabin to use the toilet (at the rear of that plane) and then he spotted a friend of his in the plane, the seat next to him empty. Drops into it and a "Comment ca va, Chef"........
Fifteen or twenty minutes later, the co-pilot wonders where his captain is and decides to go back to get him, the plane on autopilot. Walks out of the cockpit, the door closes, he's forgotten the auto-lock and they now have a plane careering on with no pilots in there.
Then, they carried an emergency axe and had to get it out to use it on the door to reenter.........wonderful confidence-building for the passengers aboard, no doubt.
I wonder if the systems exist to land the plane on autopilot or even fly it from a distance......I have been on several flights where they have used autopilot on landing, esp in fog, and they are usually the smoothest, the plane coming right down on its parabolic curve.....