What impact did World War II have on the economy of the USA?
During the War itself, the economy was mobilized to support the war effort. The War Production Board was created to convert industrial production to war production. For that reason, automobiles were not manufactured during the war years, neither were refrigerators or other items containing metal and other products which could be used in the war effort. Most famously, pennies during 1943 were made of steel rather than copper. Some few are still in circulation. The Office of Price Administration set price ceilings which created shortages of some items. Sugar, coffee, gasoline, meat, and tires were rationed by means of government coupons. Wage and price controls were implemented and if unions threatened to strike over wage freezes, the company risked government seizure. Ironically, the production of war materiel went much further in pulling the U.S. out of the Great Depression than had any of Roosevelt's New Deal programs.
After the war, rather than the anticipated recession, the economy boomed because of pent up demand for consumer goods which had not been produced during the war years. This together with Social Security and the Serviceman's Readjustment Act (which provided millions for education, home purchases and medical care for veterans) caused the economy to grow at an exceptionally fast rate. From 1940 until 1952, the Gross National Product (GNP) grew from $101 Billion to $347 Billion.