Air Mail Mystery is an Old Time Radio show centered around the early, dangerous days of air mail delivery. The story takes place at Trans American Airlines, where planes carrying important mail have been mysteriously crashing. The show explores the possibility of sabotage or bad luck as the cause of these accidents. The main characters include Ernest Powers, the general manager of Trans American, pilot Andy Andrews, undercover mechanic Fitzgerald, Justice Department agent Irene Delroy, and reporter Jimmy Gifford. The show captures the risks faced by early pilots, the evolution of mail delivery, and the massive profits that could be made through government mail contracts. As the investigation unravels, the relationships and true identities of the characters are revealed, creating an engaging and suspenseful storyline for listeners.