I have no idea how "great" a pilot Ernest Gann was. But he was successful in the the age when flying was dangerous, and sex was safe.
And he was unsurpassed in his tale-telling, giving the reader a magnetic sense of 'being there', learning the hard lessons just as he had.
And his humor - when telling hairy situations - was a real talent. The last few chapters of Gann's Band Of Brothers are a treat!