During the Skelly years, listeners could join the Flight Patrol by going to a Skelly gas station, where they could get a bronze Medal of Membership. This soundbyte is from the introduction to one of the earliest broadcasts in 1939, where the announcer (probably Don Gordon) encourages the kiddies to take their parents to their local Skelly Oil dealer, and join the Flight Patrol - to get a bronze medal with spinning propeller, and the mysterious secret password.

In 1940, the show was acquired by Ovaltine and was broadcast nationally. Captain Midnight (a code-name for a young Air Corps officer, Capt. Albright) was recruited to head the Secret Squadron, a paramilitary organization formed to fight espionage and sabotage. His companions included Chuck Ramsay, Joyce Ryan, and Ichabod Mudd, a talented mechanic.

During the Ovaltine years, listeners could join the Secret Squadron by sending in an Ovaltine Label. They would receive a Code-O-Graph, which identified them as members of the Secret Squadron, and with which they could decipher Secret Squadron Signal Session messages at the end of the show, which gave a hint about the following day's adventure. Here is a two-minute example of the Secret Squadron Code message from one of the "Suicide Squadron" episodes, originally broadcast in 1942. The announcer is Pierre Andre.