 The film ends with an epilogue chronicling the contributions of the Royal Canadian Air Force (RCAF) to the making of the film.Brian MacLean (James Cagney) irritates fellow bush pilots Johnny Dutton (Dennis Morgan), Tiny Murphy (Alan Hale Sr.), Blimp Lebec (George Tobias), and British expatriate Scrounger Harris (Reginald Gardiner) by outcompeting them 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.