Deployment of forces to South Vietnam
Seal of Royal Thai Army Expeditionary Division
To support South Vietnam against Communist attacks
Date1967 – 1972
Casualties - 351 killed - 1,358 injured
The official American military presence in Thailand started in April 1961 when an advance party of the USAF 6010th Tactical (TAC) Group arrived at Don Muang Royal Thai Air Force Base at the request of the Thai government to establish an aircraft warning system at Don Muang. The USAF presence grew rapidly with the expansion of the Laotian Civil War and the Vietnam War.
The USAF would eventually use 8 airbases in Thailand: Don Muang, Korat, Nakhon Phanom, Nam Phong, Takhli, Ubon, Udorn and U-Tapao.
Military Police stop traffic to allow the 2 1/2 ton trucks carrying members of the Black Panther Division to leave Newport Docks, enroute to Bearcat, 22 July 1968The People's Army of Vietnam Special Forces infiltrated into Thailand several times to attack these airbases, with a 1972 raid on U-Tapao seeing three Boeing B-52 Stratofortress bombers being damaged with several sappers and a Thai sentry killed. 
Over the course of the war, the United States poured $1.1 billion in economic and military aid into Thailand, while USAID poured in another $590 million, both aiding Thailand's economy and indirectly paying for the cost of Thailand's participation and then some. At the height of the war, some 50,000 American military personnel (mostly Air Force) were stationed throughout Thailand. Thai entrepreneurs built scores of new hotels, restaurants and bars to serve the waves of free-spending American G.I.s, causing foreign funding to flow into the country. At the war's end, Thailand kept all military equipment and infrastructure left by the Americans, aiding in the country's modernization.
On 14 October 1973 following the 1973 Thai popular uprising, former Supreme Court Judge Sanya Dharmasakti, then chancellor and dean of the faculty of law at Thammasat University, was appointed prime minister by royal decree, replacing the succession of staunchly pro-American and anti-Communist military dictatorships that had ruled Thailand previously.
With the fall of both Cambodia and South Vietnam in April 1975, the political climate between Washington and the government of PM Sanya had soured. Immediately after the news broke of the use of Thai bases to support the Mayaguez rescue, the Thai Government lodged a formal protest with the US and riots broke out outside the US Embassy in Bangkok. The Thai government wanted the US out of Thailand by the end of the year. The USAF implemented Palace Lightning, the plan to withdraw its aircraft and personnel from Thailand. The SAC units left in December 1975; and the 3rd Aerospace Rescue and Recovery Group left on 31 January 1976, however the base remained under US control until it was formally returned to the Thai government on 13 June 1976.
Tahan Sua Pran or Tiger Soldiers - Through an agreement worked out primarily between the US military the Thai military and the CIA, A group that was called the Tahan Sua Pran or Tiger Soldiers were recruited off the streets of Bangkok and trained by the US Special Forces to act as a quick reaction force.
PARU - Border Patrol Police Aerial Reinforcement Unit, . The CIA assigned Bill Lair to work with the Thai Police on a project to provide faster reaction to events than the Thai Military. This unit was to act as the Thai vanguard against this kind of thing. To jump into an area, and rally support.
Naval Special Warfare Command (Thailand)
Royal Thai Volunteer Regiment (Queen's Cobras). The Royal Thai Volunteer Regiment (Thai: กรมทหารอาสาสมัคร), or the Queen's Cobras (จงอางศึก) was a unit of the military of Thailand which served in the Vietnam War. The unit of some 2,000 troops served alongside the American 9th Infantry Division from 1967–1968, when they were replaced by the Royal Thai Army Expeditionary Division ("Black Panthers").
Forward Air Guides (FAGs) Thailand, https://www.academia.edu/82394581/Thai_Forward_Air_Guides_in_the_War_in_SE_Asia
late 1970, numerous allied and enemy troops were on the ground, and the battle tempo had increased, making the battlefield in Laos increasingly dangerous. In April 1971, a US pilot mistakenly dropped ordnance on a group of Thai troops, killing 16, including two Thai commanders. Clearly, more FACs were needed on the battlefield to coordinate airstrikes. In response, CIA institutionalized the concept of forward air guides, ground-based controllers given a unique, if uncomfortable, acronym—FAGs—to differentiate them from airborne FACs. Commenting on the program, Maj. Gen. Richard Secord, an Air Force officer detailed to CIA in the late 1960s in Laos, stated, “The FAGs—and the designation FAG was not liked—were used on the ground. This arrangement was contrary to the dogma that you had
to be a fighter pilot [to be a forward air controller]. You didn’t [really] need to be a fighter pilot to be a
FAC. Maybe this made better FACs, because they weren’t aspiring to become chief of staff. The job takes
knowledge of airmanship, even if a man is not a pilot.” CIA began recruiting over 100
military-aged, English-speaking males in Thailand, sending them to a 10- to 14-day combat controller
(CCT, essentially FAC) class taught by USAF CCTs at Udon Thani \RTAFB. After graduation, the new
guides would serve on the Laos battlefield as CIA contract employees.
The FAGs played a role in modern warfare so unique and anomalous it
had never been seen before the war and has not been seen since. These
individuals were given “validation authority” to clear US aircraft to
strike targets, perhaps the only time in the history of US warfare that
non-US civilians were granted such authority. A FAG’s primary duty
in Laos was to assist US and allied forces to identify and attack targets,
and then to conduct battle damage assessments (BDA) of the effects of the
strikes. Because FAGs had developed the skill to coordinate aircraft strikes,
they were also called upon to help Thai artillery batteries home in on
enemy targets. FAGs performed secondary roles as CIA liaison with Thai ground forces, and CIA paramilitary officers typically shared with them indications, warning, and other intelligence to
inform Thai units. Other duties FAGs performed for CIA and the Thai battalions included coordination of US
medical evacuation (MEDEVAC) and logistical aircraft services.
CIA Secret Warriors: Thai Forward Air Guides by Dr. Paul Carter
YouTube Video on FAGs
OFFICE OF ACADEMIC RESOURCES
Chulalongkorn University, Paul Turner Carter
United Nations Report on Human Rights