War rationing caused the most significant change in men's suits during the 1940s. Although the shape changed little, vests, pocket flaps, and trouser pleats and cuffs were removed to conserve material. In contrast, the flashy zoot suits, occasionally worn by young men, boasted baggy pants and large, wide shoulders. With the end of war rationing came longer, full cut suits. Men's hair was longer and greased back during the 1940s, especially for teenagers and young men. This contrasts the popular crew cut of the 1950s.
Notice in the image of the zoot suit below the baggy cut of the pants and trousers and the wide shoulders.
Teenage boys of the 1940s typically wore high-waisted pants or jeans, with turned up cuffs, white socks, and penny loafers. T-shirts, collared shirts, or pullover sweaters were worn.