Secret Service of the Air (also known as Murder Plane) is a 1939 American adventure film directed by Noel M. Smith and starring Ronald Reagan.

The series consisted of four films, all starring Ronald Reagan as Lieutenant "Brass" Bancroft of the U.S. Secret Service and Eddie Foy, Jr. as his sidekick "Gabby."

Brass learns that the smugglers use the Los Angeles Air Taxi Company, where he lands a job (after Saxby has the regular pilot arrested).

With his friend and radio operator, "Gabby" Watters (Eddie Foy Jr.), Brass convinces the ringleader, Jim Cameron (James Stephenson), to let him take over the smuggling flights.

The Glendale Airport was at the time the major airfield serving Los Angeles, but after World War II with larger aircraft and jet airliners it could not accommodate, it closed in the mid-1950s.