Hop Harrigan (Bakewell) and his pal "Tank" Tinker (Getchell) operate a small airport and flying service where they are hired by J. Westly Arnold (Vogan) to fly scientist, Dr. Tabor (Merton), to his secret laboratory where he has a revolutionary new power unit. But an unknown character known as The Chief Pilot (Oakman)is interested in the invention and uses a destructive ray to cripple Hop's airplane and kidnap Tabor. Hop and "Tank", aided by Gail Nolan (Jennifer Holt and her kid brother, Jackie (Robert 'Buzz' Henry), finally overcome the criminals only find a bigger threat to them all within their group...
- William Bakewell as Hop Harrigan. Bakewell is older than the character he is playing but a "convincing enough hero."
- Jennifer Holt as Gail Nolan
- Robert 'Buzz' Henry as Jackie Nolan
- Sumner Getchell as "Tank" Tinker
- Emmett Vogan as Arnold
- Claire James as Gwen Arnold
- John Merton as Dr. Tobor
- Wheeler Oakman as Alex Ballard
- Ernie Adams as Retner
- Peter Michael as Mark Craven
- Terry Frost as Barry
- Anthony Warde as Edwards
- Jackie Moran as Fraser
- Bobby Stone as Gray
- Jack Buchanon as Deputy Sheriff