In Superman (1978), Kirk Alyn and Noel Neill have cameos as the parents of Lois Lane, in a train that is being passed by a running, teenage Clark Kent. Their scene was essentially cut from the original theatrical release but restored in the subsequent extended edition.
Kirk Alyn was credited only as Clark Kent because the studio felt that no one should know who was playing the part of Superman. In fact, they spread the story that Superman was portraying himself in the serial.
Considered to be the most successful serial of all time.
Due to the crudity of special effects at the time (and the incredibly high cost of portraying it convincingly) all images of Superman in flight were animated in a manner similar to the way Superman flew in the Fleischer Studios cartoons of the early 1940s. Sometimes animated images were even superimposed onto live-action shots.
This serial marks the very first live-action portrayal of Superman.