What were the economic consequences of President Franklin D. Roosevelt's 1941 declaration of war?

The declaration of war by President Roosevelt in 1941 had an impact on our economy. The United States was still dealing with the effects of the Great Depression in 1941, and the support for continuing and/or expanding some New Deal programs had been fading for a few years. Entering World War II helped to bring our economy out of the Great Depression.
Many things changed when we declared war in 1941. We needed many soldiers to fight in the war. Millions of Americans served in the military during World War II. We also needed many workers to produce the supplies and equipment that were needed to fight the war. Planes, ships, guns, and uniforms were just a few things that needed to be produced in our factories. The government increased its spending to conduct the war. The declaration of war positively impacted our economy. Unemployment dropped, and the economy grew because of the increased spending. Our gross national product doubled in six years after the declaration of war was issued.
Our economy was positively impacted by the declaration of war in 1941.
https://www.dummies.com/education/history/american-history/u-s-economy-and-industry-during-world-war-ii/