It was originally activated as the 20th Transport Squadron in 1940 and served as a troop carrier unit in Panama during and after World War II, until it was inactivated in 1949.

Activated in 1965 as the 20th Tactical Air Support Squadron, it served notably for seven and a half years of combat duty during the Vietnam War, and was inactivated in 1973.

The C-47s were followed on 19 June by two Consolidated OA-10 Catalina amphibians (which flew rescue missions in both the Pacific and Caribbean)[3] and a locally procured Stinson C-91.

One replacement aircraft received by the squadron was the huge Boeing XC-105, which was converted from bomber to heavy transport configuration to meet Sixth Air Force's peculiar requirements for long frequent over-water resupply flights to Seymour Field in the Galapagos Islands.

But the unit also got the first two Fairchild UC-61 Forwarders, a new Douglas C-47A and conducted long-distance flights with cargo and personnel to resupply and evacuation of the small radar sites spotted around the periphery of the Canal.

The last year of the war, with the general wind-down of the size and breadth of Sixth Air Force, saw a gradual reduction in the previously hectic flight schedules for 20th crews.

[1] Routine transport operations within Panama, South and Central America continued, with a C-47 aiding a forest fire in the Peten region of Guatemala.

[citation needed] After the end of the war, the squadron continued to provide transport for Caribbean Air Command, and was equipped with Douglas C-54 Skymasters in 1946.

While at Smyrna, the 20th trained with U.S. Army paratroopers from Fort Campbell, Kentucky in airborne tactics and carried cargo about the United States.

The squadron inactivated on 20 October 1949 and most of its remaining resources were absorbed by the 316th Troop Carrier Group, which activated at Smyrna in November.

It ran check flights for newly assigned aircrews, as well as flew visual reconnaissance and forward air control missions under various call signs.

The army was reluctant to surrender the Forward Air Control (FAC) role, but had agreed to do so under an inter-service agreement that allowed them to have helicopters.

By the end of 1965, the 20th TASS was assigned the mission of directing interdiction of the Ho Chi Minh trail; this was dubbed Operation Tiger Hound.

The squadron's original forward operating bases were at Khe Sanh, Kham Duc, and Kon Tum, which were very close to the Ho Chi Minh Trail, unlike Da Nang, which was the width of the country away.

Vietnam People's Army and Viet Cong antiaircraft defenses were increasingly sophisticated and dangerous, however, and the slow, unarmored O-1 was ever more vulnerable to ground fire.

[citation needed] Its lack of weaponry was also frustrating, as FACs could watch the enemy disappear while the strike aircraft were still en route.

[9] The aircraft carried more ordnance, was capable of longer loiter times, had more power, and featured improved conventional navigation aids and in-flight instrumentation.

[10][13] On 11 July 1972 Major John Leonard Carroll a 20th TASS pilot on temporary duty with the 56th Special Operations Wing at Nakhon Phanom Royal Thai Air Force Base and flying an O-1G Bird Dog as a Raven FAC, earned the squadron's third Air Force Cross.

His aircraft was shot down over the Plaine des Jarres, Xiang Khoang Province Laos, and he was killed on the ground shooting it out with two PAVN companies attempting to capture him.

During training exercises, the 20th deployed to and flew from bases in Italy, Spain, Denmark, Turkey, England, Belgium, West Germany, and The Netherlands.

The 20th TASS was activated again on 1 April 1990 at Shaw AFB, South Carolina, as part of the 507th Tactical Air Control Wing, it was inactivated 31 December 1991.

A geographically separated unit, the squadron is assigned to the 432d Operations Group[1] of the 432d Wing, both of which are located at Creech Air Force Base, Nevada.

[citation needed][1] The 20th Reconnaissance Squadron flew the General Atomics MQ-1 Predator remotely piloted aircraft on missions that include route reconnaissance, target marking, on-scene commander, intelligence-surveillance-and-reconnaissance, close air support and generally providing eyes, ears, and voice above the battlefield.