Takhli Royal Thai Air Force Base (IATA: TKH, ICAO: VTPI) is a Royal Thai Air Force (RTAF) facility in central Thailand, approximately 144 miles (240 km) northwest of Bangkok in Takhli District, Nakhon Sawan Province.

CIA-operated C-130A Hercules transports flew men and supplies over Indian airspace, with the consent of Prime Minister Nehru, for parachute drops into Communist Chinese-occupied Tibet.

[2] Political considerations with regards to Communist forces engaging in a civil war inside Laos and fears of the civil war spreading into Thailand led the Thai government to allow the United States to covertly use five Thai bases beginning in 1961 for the air defense of Thailand and to fly reconnaissance flights over Laos.

Thailand-based aircraft flew missions mostly into Laos until the 1964 Gulf of Tonkin Resolution which expanded the air war into North Vietnam.

[3] The 331st ABS came under the command and control of 35th Tactical Group at Don Muang Royal Thai Air Force Base, near Bangkok.

The 27th TFW kept a rotational Temporary duty assignment (TDY) of three squadrons of F-100s in Takhli until November 1965 when F-105 Thunderchiefs began to arrive on a permanent basis.

[15] The permanent assignment of the 355th Tactical Fighter Wing to Takhli in December 1965 ended the temporary squadron rotations from continental US bases.

On 31 October 1965 Takhli-based F-105s conducted a joint operation with the US Navy to attack North Vietnamese surface-to-air missile (SAM) sites.

[9]: 192 In order to support the buildup of US airpower in Southeast Asia as a result of the Gulf of Tonkin Incident, in early August 1964, 8 KB-50Js of Detachment 1, 421st Air Refueling Squadron, was deployed at Takhli from Yokota AB, Japan.

In January 1967, the SAC 4258th Strategic Wing assumed full responsibility for the Takhli KC-135 tankers formerly belonging to the 4252d SW at Kadena AB, Okinawa.

In November the Detachment returned to Osan AB and was replaced with HH-43Bs transferred from Bien Hoa Air Base, South Vietnam.

[16]: 70 In June 1965 a TDY unit of 2 C-130s from E Flight, 21st Troop Carrier Squadron began airlift operations from Takhli into Long Tieng, Laos in support of the CIA and the army of Major General Vang Pao.

[17] On 8 November 1965 the 355th Tactical Fighter Wing made a permanent change of station from McConnell AFB to Takhli without personnel or equipment as the host unit at the base.

Previously, all of the 355th's squadrons at McConnell had been deployed to various bases in Southeast Asia, two of which were reassigned to Takhli (357th, 354th TFS) and brought back under its control.

On 10 March 1967 Air Force Captain Max C. Brestel, flying from Takhli, became the only F-105 pilot to shoot down two MiGs during the Vietnam War.

[15]: 111 On 10 March 1967 355th TFW F-105s took part in the first attacks on the Thái Nguyên ironworks, Captain Merlyn H. Dethlefsen won the Medal of Honor for actions including destroying two SAM sites during a mission from Takhli.

[15]: 110 In November 1967, Gerald Gustafson received the Air Force Cross after he refused to leave his comrade until other escort aircraft could be vectored in to give the wounded pilot assistance in reaching his home base safely.

The Wild Weasel concept was originally proposed in 1965 as a method of countering the increasing North Vietnamese SAM threat, using volunteer crews.

Sometimes they, or the strike aircraft with them, would fire a radar-seeking AGM-45 Shrike missile which followed the SAM site's radar beam right back down to the transmitting antenna.

[24] The herbicide spraying missions began in Vietnam in 1961, and it has recently been revealed that some took place from Thai bases, including Takhli, as early as 1966.

The missions in 1966 defoliated areas surrounding parts of the Ho Chi Minh Trail in Laos, near the Vietnam border and north of the Vietnamese Demilitarized Zone and had the approval of both the Thai and Laotian governments.

It turned out that the third loss on 22 April was not due to enemy action, but was traced to a failure of a hydraulic control-valve rod for the horizontal stabilizer which caused the aircraft to pitch up uncontrollably.

From 10 November 1970, Special Forces and Air Force Special Operations personnel of the Joint Contingency Task Group and two MC-130 Combat Talon aircraft staged at Takhli in preparation for Operation Ivory Coast, the attempt to rescue US prisoners of war (POWs) from the Son Tay prison camp in North Vietnam.

On 30 June the 366th Tactical Fighter Wing was reassigned to Takhli from Da Nang AB, South Vietnam, taking over host unit responsibilities from the 49th TFW.

The 366th TFW was inactivated in place on 31 October 1972, being reactivated the same day without personnel or equipment at Mountain Home Air Force Base, Idaho.

[15]: 246 The 474th's F-111s also participated in Operation Linebacker II in December 1972 flying 154 night/single-ship sorties into the high-threat area of North Vietnam with the loss of 2 aircraft.

[15]: 269 In early 1973, with the suspension of bombing in North Vietnam and the resumption of peace negotiations, inflight refueling requirements decreased markedly.

[18]: 183 For a brief two-week period the 347th flew combat operations into Cambodia until 15 August, when the final mission of Constant Guard IV was flown.

[16]: 136 On 31 July 1974 phase down of operations at Takhli RTAFB was completed ahead of schedule, and the base was officially returned to the Thai Government on 12 September.

The American withdrawal had quickly revealed to the Thai government the inadequacy of its air force in the event of a conventional war in Southeast Asia.