 The characterization of Neville Sinclair was inspired by movie star Errol Flynn , or rather by the image of Flynn that had been popularized by Charles Higham 's unauthorized and fabricated biography of the actor , in which he asserted that Flynn was , among other things , a Nazi spy . The film 's Neville Sinclair is , like Higham 's Flynn , a movie star known for his work in swashbuckler roles , and who is secretly a Nazi spy . Because Higham 's biography of Flynn was not refuted until the late 1980s , the image of Flynn as a closet Nazi remained current all through the arduous process of writing and re @-@ writing the script . The other real @-@ life characterization was of Howard Hughes . 
