Mystery of the Flying Monster

It's a bird! It's a plane! It's a complete Superman radio adventure from March 7, 1949!
Debuting on March 12, 1940, The Adventures of Superman was an instant hit. It starred Clayton "Bud" Collyer in the dual roles of Superman and Clark Kent, and was a radio mainstay until its final episode in March 1951. In all, "Bud" Collyer played his most famous roles in more than 2,000 episodes.