How are stereotypes employed in Walter Mitty's daydreams?

Walter Mitty identifies himself with stereotypical characters in all of his daydreams. In the first episode he becomes a gallant naval officer.

He wore his full-dress uniform, with the heavily braided white cap pulled down rakishly over one cold gray eye. 

The narrator does not say so, but Mitty must have noticed a few drops of mist on his windshield and realized that a storm was approaching. This is what triggered his daydream. Mitty realizes...

Walter Mitty identifies himself with stereotypical characters in all of his daydreams. In the first episode he becomes a gallant naval officer.

He wore his full-dress uniform, with the heavily braided white cap pulled down rakishly over one cold gray eye. 

The narrator does not say so, but Mitty must have noticed a few drops of mist on his windshield and realized that a storm was approaching. This is what triggered his daydream. Mitty realizes that he is responsible for getting his wife and himself into Waterbury and back to their suburban home. The approaching storm will provide "framing" for the story. It limits Mitty's endless daydreams to just five episodes and gives a sufficient impression of his "secret life. In the end the storm will finally break and he will back up against the wall of the drugstore and light a cigarette.

The second daydream is triggered by Mrs. Mitty's suggestion that he see Dr. Renshaw. Mitty becomes a stereotypical expert surgeon involved in a crisis situation in an operating room. It is noteworthy that he always places himself in roles that are appropriate for his age. He does not indulge in fantasies in which he is a young lover or a great athlete.

In his third daydream Mitty is a master marksman and a sort of aristocratic man of the world or soldier of fortune--the type of hero who might be featured in British thriller novels or the Ashenden stories of Somerset Maugham.

In the fourth episode Mitty becomes a World War I ace pilot after glancing through an article in Liberty magazine which shows that the time of the story is shortly before the outbreak of World War II. Mitty cannot be middle-aged in this episode, but he can backdate the episode. This is the only daydream in which Mitty retreats into the past. Mitty has to be a World War I ace pilot because he knows he is far too old to be air ace in World War II, a conflict which everybody knows is sure to come and fairly sure to involve America eventually. "The Secret Life of Walter Mitty" was published in the March 18, 1939 issue of the New Yorker. Britain and France declared war on Germany on September 3, 1939.

In the last daydream, the storm he foresaw on the way to Waterbury has finally broken. Mitty imagines that he is facing a firing squad, another stereotypical situation. He is probably a master spy being executed, although this is not specified. The storm not only provides a beginning and ending for the story, but it seems to symbolize the unhappiness which Walter Mitty tries to assuage by indulging in his fantasy life. He is growing old. His life is dull. His future looks bleak. He is married to a bossy woman he no longer loves--if he ever did. He wouldn't mind being shot by a firing squad.