Though World War II was terrible and tragic because of lost lives, destroyed cities, and the Holocaust, it was good for the American economy. Providing materials for the war propelled the United States out of the Great Depression. Starting in 1939, the year the war began in Europe, jobs in the US abounded and the once high unemployment levels dropped virtually overnight. Suddenly, everyone could find a job.
Once the United States got into the war in late 1941, the economic situation only got better. It has been said that supply lines win wars, and the US was a huge supply line, putting its industrial might into churning out a seemingly endless number of planes, tanks, jeeps, uniforms, guns, grenades, and uniforms. With most of the men away at war, women worked around the clock in factories. Because of rationing, there was not much to buy, so people saved their money.
After the war, people quickly converted their savings into material goods, buying cars, clothes, houses, washing machines, and other consumer items in a frenzy of pent-up demand that fueled economic growth. Further, with most of Europe in shambles, the world depended on US factories to supply the goods and materials needed for rebuilding. After the war, the US took its place as the world's economic powerhouse.