In late 1941 the Japanese Zero fighter was gaining an aura of invincibility, winning a high percentage of its battles. It was a good aircraft, but it did have its drawbacks, one of, which were its slower speeds and its inability to withstand high-speed dives. It won most of its fights with it's outstanding agility at low speeds and altitudes.

Claire Lee Chennault was a former colonel who had retired from the U.S. Army Air Corps because his theories on tactics were so at odds with the fiercely conservative Air Corps brass. He was asked to help modernize the Chinese Air Force and quickly became friends with Chaing Kai Shek and his lovely wife. The retired colonel wrote a report about the deadly Zero and sent it to the U.S. government. It was promptly filed away. This was a mistake. If the threat had been taken seriously and if American pilots had been trained to deal with such a fighter, the Japanese would likely have sustained much heavier losses in the early air war.

Col. Chennault built up a group of Curtiss P-40s in his Chinese redoubt. At most there were 50 operational at any time, piloted by a band of mercenary pilots, nearly all Americans. The Chinese called them the Fei Hu, Flying Tigers and the name stuck. Officially they were known as the American Volunteer Group. They began combat operations on 20 December 1941 and officially disbanded on 4 July 1942. They were composed of three squadrons, The Adams and Eves, The Panda Bears and The Hell's Angels.

Flying P-40s adorned with fearsome shark's mouths shattered the myth of Japanese invincibility and almost single-handedly saved China. Amazingly, this ragtag group of renegades, or so their Japanese opponents called them, fought using only fifty or so planes at a time and downed several times that many. In fact they had an unbelievable kill ratio of 70 to 1. 296 (although some sources say 286) enemy aircraft confirmed and an additional 153 probables for a loss of only 12 planes and 3 pilots in air combat. An even more impressive feat considering that the American mercenaries had virtually no combat experience while the Japanese had been fighting in China for years.

The keys to their success was understanding their enemy, the tactics they employed, Col. Chennault's uncanny ability to predict the enemy's next move and an aircraft that excelled in their method of fighting. The early warning net (a primitive yet effective network of spotters and radio operators set up to report enemy aircraft) would report the position, direction and estimated altitude of incoming Japanese aircraft. The Flying Tigers would climb above the enemies' altitude on an intercepting course. On sighting the Japanese they would dive on them at high speed and slash through their formation, guns blazing. After the attack the Tigers would use the speed from the dive to exit the combat zone and climb for another pass. It was essentially a drive-by shooting.

The P-40 could climb above 15,000 feet in 5 minutes and could dive at 480 mph. The Japanese Zero would lose its wings at this speed and it couldn't climb as fast. The P-40s wisely did not stick around to dogfight with the Zeros at low altitudes because that was were the Zero excelled.

A few volunteers were displeased with this tactic and resigned. This method of fighting also did not go over well with the Chinese and British flyers in the area, either. Initially, British pilots seen diving away from combat would be court-martialed; Chinese pilots seen doing the same would be shot. However, as the Flying Tigers' success mounted other units with suitable aircraft adopted their tactics and it no longer was unfashionable in air-to-air fighting to dive away and live to fight for another dive.