Before the Americans arrived, U-Tapao was a modest Royal Thai Navy airfield near Ban Chang in Rayong Province, on the Gulf of Thailand. In 1965, the United States needed a Southeast Asian base for its large jet aircraft, and the small Thai naval strip offered a solution. The US began construction on October 15, 1965, and completed the runway and facilities in eight months. The base was handed to the RTN on August 10, 1966. By September, KC-135 Stratotanker refueling aircraft were operating from the field. The USAF had been flying B-52 bombing missions from Kadena Air Base on Okinawa, but Okinawa was too far from Vietnam to meet the escalating demands of Operation Arc Light. U-Tapao had an existing runway, the cost of upgrades was minimal, and -- critically -- it was close enough to Vietnam that B-52s could fly combat missions without mid-air refueling.

On March 2, 1967, the Thai government approved the stationing of 15 B-52s at U-Tapao. The first three bombers landed on April 10, arriving from a bombing mission over Vietnam. The next day, B-52 sorties began flying directly from Thai soil. By 1972, 54 B-52 aircraft were stationed at the base. From 1966 to 1970, the 4258th Strategic Wing's tankers alone flew over 50,000 sorties from U-Tapao. Under Operation Arc Light, wing bombers flew more than 35,000 strikes over South Vietnam between 1967 and 1970. During the Battle of Khe Sanh in early 1968, U-Tapao-based B-52s dropped bombs as close as 900 feet from the Marine perimeter, flying 2,548 sorties and delivering 54,129 tonnes of ordnance in defense of the besieged outpost.

U-Tapao played a central role in the war's most intensive bombing campaigns. When North Vietnam launched a full-scale offensive across the DMZ in March 1972, 51 B-52s were based at the field. In December 1972, Operation Linebacker II unleashed 129 B-52s in three waves against North Vietnam -- the U-Tapao-based B-52Ds carried more bombs and flew more sorties than units operating from Andersen Air Force Base on Guam, which had to fly much farther. On January 10, 1972, three communist sappers had attempted to destroy B-52s on the ground using grenades and satchel charges; one attacker was killed, and the other two caused only minor damage before escaping. In April 1975, as Saigon fell, U-Tapao became a final way station -- South Vietnamese aircraft flew in from their last combat missions, and 27 A-37s, 25 F-5s, and 50 UH-1 helicopters were loaded onto ships for transport to the United States.

Less than two weeks after Saigon's surrender, the Khmer Rouge seized the American container ship SS Mayaguez, and U-Tapao served as the staging point for the rescue mission. The operation's use of Thai bases without Thai consent triggered a diplomatic crisis -- riots broke out at the US Embassy in Bangkok, and the Thai government lodged a formal protest. American forces departed in 1976, but U-Tapao's strategic value endured. Since 1981, it has hosted the annual Cobra Gold exercises with US, Thai, and Singaporean forces. It coordinated humanitarian relief after the 2004 Indian Ocean tsunami. Today it remains the Royal Thai Navy's main flying base, home to squadrons of Dornier patrol aircraft, P-3 Orions, and Seahawk helicopters -- a working military airfield still shaped by the runway the Americans built in eight months during 1965.