Brian MacLean (James Cagney), Johnny Dutton (Dennis Morgan), "Tiny" Murphy (Alan Hale Sr.), "Blimp" Lebec (George Tobias), and British expatriate "Scrounger" Harris (Reginald Gardiner) are bush pilots competing for business in rugged Northern Ontario, Canada in 1939, as the Second World War is beginning. Dutton, whose ambition is to start his own airline, flies by the book but MacLean is a seat-of-the-pants kind of pilot, mirroring the differences in their personalities.