Trying to land an airplane in the absence of a pilot

When you are being driven by somebody else, and something happens to the driver, most people will attempt to take over the driving themselves. Even if that fails, there is a good chance that even an accident will not lead to severe injuries; what happens when the controls are more complicated, and the injuries / damages that would happen in an accident are more likely to happen ? We are so dependent on air travel that we do not even try to consider the case of what happens when something happens to the pilot of the aircraft; well in the case of this small craft, there was a passenger who was able to fly the aircraft with some coaching (link to article):

It's a nightmarish scenario straight out of the movies: A passenger is forced to land a plane after its pilot becomes incapacitated. The reality was playing aboard a plane over Florida on Sunday in what the National Air Traffic Controllers Association called "an Easter miracle." The pilot notified controllers that the plane was at 9,000 feet and climbing, said Steve Wallace, Miami Center spokesman for the association. However, a controller at the center tried twice to raise the pilot after that and received no response, Wallace said.
After a few moments, a different voice came over the radio: Passenger Doug White told air traffic controllers the pilot was unconscious and they needed help. His wife and two teenage daughters were flying home to Louisiana with him, he said. He reported the plane's autopilot was on and the plane was continuing to climb from 10,000 feet. White later told the Naples Daily News he has a pilot's license and about 130 hours experience flying a single engine Cessna, but had never flown the larger, faster King Air.

This was a good coincidence, however, one shudders to think what would happen in the case when there was nobody available to pilot the aircraft; the family would have been acute distress at the impending disaster.