One notable group flying Mustangs was the Tuskegee Airmen’s 99th Fighter Squadron of the 332nd Fighter Group, known as the "Red Tails." They became one of World War II’s most decorated squadrons. On one mission, they faced 100 enemy planes with only 39 Mustangs, shooting down five while losing just one of their own. “Red Tails” pilots also succeeded against German jets during bomber escort missions.
Technological improvements on the P-51D included a bubble canopy for improved visibility—an innovation that helped pilots maximize their effectiveness—and an upgraded engine: a Packard-built Rolls-Royce Merlin V-1650 producing 1,695 horsepower. This enabled a top speed of 437 mph at higher altitudes and increased service ceiling compared to earlier models.
The armament was also enhanced; six .50-caliber machine guns replaced four on previous versions. A new K-14 gyroscopically stabilized gunsight allowed more accurate targeting during aerial engagements. According to available sources, American air industry output increased dramatically during WWII: by 1944 U.S. manufacturers produced approximately 96,000 aircraft per year compared to Germany's 40,000 (https://www.nationalww2museum.org/war/articles/world-war-ii-aircraft-production-numbers). Daily production rates reached up to 270 warplanes (https://www.britannica.com/topic/history-of-flight/The-modern-era#ref241589).
By war’s end, P-51Ds had scored nearly 5,000 aerial victories for U.S. forces and contributed significantly to reducing losses among bomber crews on dangerous daylight raids over Europe—the USAAF lost over 8,000 heavy bombers in this theater alone before the arrival of effective escorts like the Mustang.
The impact extended beyond Europe; in the Pacific Theater Mustangs escorted B-29 Superfortresses on bombing runs over Japan until war’s end.
After WWII ended in May 1945 with Victory in Europe Day (VE Day), many Mustangs continued serving into the Korean War before their retirement from combat roles in 1953.
"WWII is often regarded as a war that was won by the industrial base of America, which cranked out hundreds of planes, ships, tanks, and vehicles along with thousands of other critical supplies like ammo, food, and medicine."
"The Encyclopedia of Britannica online says that as many as 270 warplanes a day were produced by the American aerospace industry of WWII."
"The National WWII Museum outlines the stunning ramp-up - in 1939 America made a little more than 2,000 aircraft a year compared to 8,000 in Germany but by 1944 that was up to 96,000 compared to 40,000."