"In 1942, American policy makers were engaged in a secret debate about the feasibility of a US-British invasion of German-occupied Europe in 1943. In a classified report for the War Production Board, two economists, Robert Nathan and Simon Kuznets, concluded that it would not be possible to produce the necessary material until 1944 at the earliest. The army's chief military supply officer, General Brehon Somervell, was furious. He denounced 'this board of "economists and statisticians" ... without any responsibility or knowledge of production.' He called for the suppression of the report, which should 'be carefully hidden from the eyes of all thoughtful men.' But the argument of Nathan and Kuznets prevailed, and D-Day was a success in 1944 instead of a disaster in 1943."
The planning paid off. In 1944, the United States completed one plane every five minutes, launched fifty merchant ships a day, and finished eight aircraft carriers a month.
The Nazis were known for the Blitzkrieg, which combined German machinery and pharmaceuticals into an attack of tanks and amphetamine-fueled soldiers. But in truth, the Wehrmacht had more horses than tanks. Throughout the war, the German military relied on roughly 2.75 million horses to move supplies, artillery, and infantry, about 50 horses for each tank. By D-Day, the United States and its allies had clear superiority in numbers and in the production capacity that sustained the war."
On D-Day, June 6, 1944, the Germans could deploy only 319 aircraft. The United States and its allies deployed 12,837.
Kuznets won the Nobel Prize in Economics in 1971. By then, the economist Somervell had wanted to silence had been recognized as one of the most important economic thinkers of the twentieth century. He and Nathan helped to win the war by insisting that the war wait for the production capacity to catch up to the ambition.