At one point during the series, two planes that were doing filming for an episode accidentally collided with each other. The script was subsequently revised so that footage of the crash was included in the episode.
The two planes collided over Somis, California in late 1961 while filming a transfer scene. They were flying in formation as a character was supposed to go from one plane to another when they contacted. One plane landed, one crashed. Cliff Winters, the pilot of the plane that was spinning out of control, had two parachutes in the back seat. One was real, one was fake. He just had time to grab one before bailing out.
Fortunately, it was the genuine article.
Unfortunately, Cliff was killed at an air show in Orange County a short while later.
The series included several spectacular skydiving scenes. In one episode, there was a fist fight between two characters in midair. The scene was shot by a cameraman who was in free fall with the actors.