Amongst all fighters produced and employed by both sides of World War II, the North American P-51 Mustang stands out as the most iconic and game-changing aircraft. Although it was neither the fastest, most agile, nor most produced aircraft of the war, the P-51 was able to balance its strength and do so with an exceptional operating range, resulting in a truly versatile platform which excelled in air superiority, ground attack, reconnaissance, and long-range bomber escort role.

The story of the P-51 began not long after the start of World War II in Europe. In November 1939, the United Kingdom established the British Purchasing Commission to coordinate purchases of war supplies from the United States, particularly fighter aircrafts needed to bolster the island nation’s defenses and its vast overseas territories. The commission procured a large number of Curtiss P-40 (Curtiss Tomahawk and Kittyhawk in commonwealth services) and some Bell P-400 (Bell Caribou, later redesignated as Airacobra) which benefitted from the reliable and streamlined Allison V-1710 V12 aero engine. However, due to their lack of turbocharger the P-40 and P-400 performances suffered at high altitude which made them less suitable for the European theater.

Only a portion of the Bell P-400 order was delivered to the UK, with most ending up being shipped to the Red Air Force after a short service with the No. 601 Squadron. The Curtiss P-40, on the other hand, proved serviceable in the North African and CBI theater where their ruggedness and durability were put to good use.

By January of 1940, Curtiss-Wright was heavily committed to building the P-40 for the United States Army Air Corps (USAAC) and had little production capacity to spare. At that time, North American Aviation had already supplied the commonwealth with large numbers of Harvard trainers and approached the Commission to sell their new medium bomber, the B-25 Mitchell. Instead, the Commission asked North American’s president, James Howard Kindleberger, if his company was willing to produce P-40 under license from Curtiss.

As it turned out, chance favored the prepared mind. When approached by Kindelberger regarding the Commission's request, North American’s young chief designer Edgar Schmued immediately replied that he could design a much better airplane in three months. In a later interview, Schmued was asked if he had ever designed a fighter before. “No, but I had been carrying around in my head concepts of what I would do if ever given the chance,” he replied. “The design that became the P-51 is the result.”