Has someone with no experience at all ever taken off in a plane? Could they? I was watching Mystery Science Theater 3000 and their showing of 1970 TV movie/pilot San Fransisco International.  One of the plots in the movie involves a twelve (or so) year old boy, who, alarmed about his parents' imminent separation, wanders across the tarmac, hops into the cockpit of an Aircoupe, and flees his mother by starting the plane and taking off before anyone quite knows what's happening.  After he unsteadily flies it a bit (the best part of the movie is some stunt pilot making the Aircoupe swerve through the air like a drunken eagle), Bonanza's Adam Cartwright talks him through a safe landing.

Plenty of questions have been asked about the possibility of planes being landed by someone with no experience at all, and, of course, talk-down landings are a real thing, even if they're rarely done by anyone with zero experience.  But I'm curious about the first part, where the kid turns a key, taxis away, and is up into the California sky without even having played Microsoft Flight Simulator.

Naturally, a civilian getting into a cockpit at SFO without being stopped seems patently absurd in the security-conscious present, but times have changed.  Has anything even similar to this ever happened?  And if not (if this doesn't over-broaden my question) could a layman get a plane, single-engine or otherwise, into the air without any experience?
The Aviation Safety Network has an article listing 11 airplanes that crashed after being stolen by a non-pilot. The most recent was the Horizon Air Dash 8 that was stolen by a ground service agent in August 2018.

There are more interesting stories such as:


The guy that tried to crash a Cessna 150 into the White House (with minimal experience and training)
Ground crew member that stole and crashed an F-16 in Norway
Mechanic that accidentally took off in an English Electric Lightning
Mechanic that took off in an F-86 Sabre
15-year-old that stole a PA-34 and took off with 4 passengers, later crashing


Whether these qualify as "amateurs" is a matter of opinion. Most of them were mechanics/engineers. It would be difficult (but not impossible) for a person not familiar at all with the aircraft to get it started and manage to take off.