The Story of WWII When Germany Mocked America’s Plan for 50,000 Planes and the U.S. Built 100,000 Instead

A Bold Prediction Dismissed

On May 16, 1940, as German forces swept through France, President Franklin D. Roosevelt stood before Congress with a startling request. He declared, “I should like to see this nation geared up to the ability to turn out at least 50,000 planes a year.” At the time, the United States Army Air Corps had barely 1,700 combat planes and had produced just over 3,600 aircraft in 1939. Many doubted the goal was possible.

Across the Atlantic, German air leaders scoffed at the idea. In Berlin, Reich Marshal Hermann Göring reviewed intelligence reports and told his staff that Americans “know nothing of war production.” He mocked the thought that automobile factories could be converted to build complex aircraft, confident the plan would fail.

American Industry Rises

Yet in Detroit, William Knudsen, a Danish-born former president of General Motors, accepted Roosevelt’s call to lead production for a symbolic salary of one dollar per year. Knudsen applied mass-production methods from the automobile industry to aircraft building, coordinating companies across the country.

By December 1941, U.S. factories were turning out 2,000 military planes each month—twenty times the output of only two years earlier. Major manufacturers such as Ford, Boeing, and Douglas expanded facilities, hired thousands of new workers, and developed new assembly-line techniques that made large-scale production possible.

Willow Run and the Arsenal of Democracy

One striking example was Ford’s Willow Run plant in Michigan. Begun in 1941, it grew into the world’s largest factory under one roof, covering 3.5 million square feet. Early struggles led some to nickname it “Will it Run?” but engineers refined processes, created subassemblies, and overcame design changes. By 1944, Willow Run produced a B-24 Liberator bomber every 63 minutes, outproducing Germany’s entire bomber force.

Other companies matched that pace. Boeing’s Seattle facility built sixteen B-17s each day by mid-1944. North American Aviation produced five hundred P-51 Mustangs per month, while Lockheed turned out a P-38 Lightning every ninety minutes. Supporting industries—aluminum, engines, and electronics—expanded at similar speed.

Changing Workforce and German Miscalculations

Women entered the workforce in unprecedented numbers. By 1943, they made up more than sixty percent of aircraft plant employees, excelling at precision tasks such as wiring and inspection. German intelligence dismissed this as a sign of weakness, expecting quality to decline, but accuracy improved instead.

German leaders underestimated both American capacity and determination. Reports from their own military attachés warning of “unimaginable heights” of U.S. production were ignored. Even as American bombers began striking targets in Europe, many German commanders could not believe the scale of what they faced.

Overwhelming Numbers in the Air

By 1944, the United States was producing nearly 100,000 aircraft each year—far exceeding Roosevelt’s original goal. That included more than 16,000 heavy bombers, 35,000 fighters, and thousands of transport and multi-engine planes. During key campaigns like the Normandy invasion, Allied forces deployed over 11,000 aircraft in a single day, achieving air supremacy through sheer output.

Captured German officers later admitted they had not grasped the industrial strength of the United States. One remarked that a single American factory had produced more aircraft than their entire air force at its peak. What began as a boastful dismissal in 1940 ended with an undeniable reality: the United States had not only met Roosevelt’s challenge but doubled it, building 100,000 planes a year and overwhelming the skies.