Key point: While a great performer for its era, the Mustang wasn't suitable to the more advanced Cold War.
The North American P-51 Mustang was one of the greatest fighters of World War II.
Had life worked out differently, the Mustang could also have fought in Vietnam and flown against a Soviet invasion of Western Europe. In fact, it might even have replaced the A-10 Warthog.
The Piper PA-48 Enforcer was a modernized version of the P-51. It was the brainchild of David Lindsay, founder of manufacturer Cavalier Aircraft, who bought the rights to the Mustang in 1956.
The P-51 eventually became the Turbo Mustang III. But in 1968, in response to an Air Force search for a counterinsurgency (COIN) aircraft to fight in Southeast Asia, Lindsay moved the Turbo Mustang III and himself over to Piper Aircraft, maker of popular aircraft such as the Piper Cub. What emerged in 1971 was the PA-48 Enforcer, Piper’s bid for the COIN contract.
While fast combat jets are sexier, the idea of a propeller-driven aircraft for COIN work makes sense: their slower speed allows them to loiter over jungle to provide air support or spot guerrillas. Prop jobs are also cheaper and require less maintenance. A P-51 cost $51,000 in 1945, or about $675,000 today. The Enforcer would probably have cost around a million dollars. The A-10 Warthog cost almost $19 million apiece.