During WWII, the United States massively increased its industrial output. This was an anomaly when compared to other similar countries (mainly Western Europe and Japan) which did not grow in the same way.
There are many reasons why the United States achieved this growth. President Roosevelt was particularly dedicated to increasing industrial production. He exempted some workers in wartime industries from the draft. This allowed factories to have enough workers to continue in operation. He also encouraged the participation of women in areas that were traditionally male dominated. Finally, he focused on industries that were needed during the war, such as aluminum and aircraft.