In 1967 Operation Combat Dragon commenced in Vietnam which would be the baptism of fire for the Cessna A-37 Dragonfly. An attack version of the T-37 trainer, the intent of the Dragonfly was to provide a low-cost yet capable close air support aircraft, a role that the faster jet fighter in the theater weren't exactly tailored to perform.
Conceived by Lt. Colonel Lou Weber, a veteran of the World War Two Flying Tigers, Operation Combat Dragon would introduce the Dragonfly into combat in a unique manner- whereas most combat aircraft had their weapons certification, weapons loading and maintenance procedures hammered out in operational testing in the United States before deploying to operational units, the Dragonfly would gain its combat certification by testing in actual combat.
Thirty pilots were selected for Operation Combat Dragon, all of whom had no more than 25 hours in the T-37. All came from all types of aircraft, from fighters to transports- Weber wanted to make sure that a pilot with any experience from any level could fly the A-37 in combat. Most deploying units to Vietnam had nine month training programs stateside before heading overseas- but with the A-37, the training was going to be done "on the job". Combat missions were to be flown in the III and IV Corps area of South Vietnam and forward air controllers favored the A-37- its slower speed allowed for pinpoint accuracy in delivering weapons on target.
The unit had the provisional designation 604th Air Commando Squadron and was based at Bien Hoa AB. In its first 3,000 sorties, not a single A-37 Dragonfly was lost in combat. Operation Combat Dragon ran from August 1967 to December 1967 and in that time frame, Lt. Col. Weber's strategy was soundly vindicated with 19,000 weapons drops and the combat experience led Cessna to develop an improved version, the A-37B. After nine months in combat, the unit had flown an astounding 10,000 sorties and reflected that it only took two men to maintain and turnaround the Dragonfly where as most jet fighters required 10 or more men per plane. On many missions a Dragonfly could be turned around for the next sortie in as little as 90 minutes. The unit would average twice the number of sorties as the more advanced and faster jets in Vietnam.
Source: Air & Space Smithsonian, January 2010. "Super Tweet- The A-37 Dragonfly carried 6,000 pounds of weapons. Bonus: They hit the target" by Stephen Joiner, p42-49.