"Clay Lacy and the Amazing Human Fly" is a short video about a man who stood on top of a DC-8 plane while it flew in 1976. The stunt man, strapped tightly into a contraption to keep him in place, nearly died during the flight. Everything started out smoothly, but It began raining when the plane was up in the air. The raindrops knocked him unconscious because of how fast the plane was going. The Human Fly said the raindrops were "like bullets." Luckily he survived, but this stunt hasn't been repeated since (for good reason).
From the YouTube description:
In 1976, famed aviation businessman and movie pilot Clay Lacy was asked to fly one of the strangest stunt acts in aviation: The Human Fly. In this exclusive AVweb video, he explains how the project came into being.