It seems to me that the proper question about the red hunting hat should be “Why did the author J. D. Salinger invent it?” This brightly colored hat with its unusual shape is mainly a way of making it easier for the reader to visualize the young hero of the novel. It makes him seem to stand out in the central part of America’s biggest city and makes it easier to follow in our imagination. The hat can be taken to symbolize Holden’s immaturity. It is something only a kid would wear. It can also be taken to symbolize his rebelliousness and militant independence, because people in the 1940s dressed conservatively and dressed alike. The hat might also be taken to suggest that Holden is “hunting” for something. A weakness in Salinger’s novel is in the hero’s motivation. He seems to act on impulse and at random. The red hunting hat at least suggests that he does not have an objective, that he is a hunter and is hunting for something. That would explain why Holden bought the hat in the first place. He feels he wants to find something, but he doesn’t know what he is looking for. When he gives the hat to his sister Phoebe it is as if he is giving up his childhood.
holden's feels his hat is his protector & comforter..there are many instances in the book in which holden feels better after putting on the hat..he wears the ear flaps in the hat to protect from cold..even at the end when phoebe puts holden's hat on his head he feels good....to me holden is just a casual teenager to whom even silly things like wearing hat can be confidence booster.