Probably one of the ten most well known aircraft in history and also the first US aircraft that went into really large scale production. The P-40 was basically a mating of a P-36 airframe with an Allison in-line, liquid cooled engine. While the engine gave good performance at low level, at altitudes above 20,000 feet it was not exactly a sterling performer. This rugged airframe was used in all theaters of war during WWII and by many Allied air forces. It gained its greatest fame from its use by the American Volunteer Group (AVG), better known as the Flying Tigers. When the unit's brief 6 month history came to an end in July of 1942, it was incorporated into the USAAF as the 23rd FG. Even today, the 23rd continues operations from bases in the East Coast of the US.