In WWI, before becoming a spymaster, William Stephenson was flew a Sopwith Camel biplane, downed 12 other planes and became a fighter ace. He was shot down behind enemy lines by the German ace Justus Grassman. Stephenson was held as a prisoner of war for roughly three months before he was able to escape.
As a reward for Fleming's 70-page memo on an ideal intelligence agency, Bill Donovan later rewarded him with a .38 Colt revolver with the inscription "For Special Services."
The idea to arrange for a corpse to wash up ashore with misleading information, known as Project Mincemeat, was indeed included in a memo circulated by John Godfrey, and almost certainly written by Ian Fleming. However the idea originated in the novel "The Milliner's Hat Mistory (1937) by Sir Basil Thompson.
Despite the disclaimer that "Some names, paces and incidents are fictitious ...", the scene of Fleming and Monday looking amongst a room of bodies for one to play 'Major Martin' is a major exaggeration. It is widely accepted that the body of 'Major Martin' was not selected from the casualties from sinking of HMS Dasher, which is what this scene purports to show.