 was still largely a Vietnamese conflict, with virtually no direct US involvement. The Geneva Accords specifically banned any foreign troops or bases from Vietnam, and the US government had agreed to limit its military presence to a 685 man Military Assistance Advisory Group. Under pressure from the USA as well as from the Vietnamese themselves, the French had authorized the creation of the Republic of Vietnam Armed Forces in 1950. These were still of moderate size when the USA took over the military training duties from France in 1955, but by 1961 the army had grown to 170,000 men, organized along US lines and using US equipment. They initially outnumbered the Viet Cong forces by a factor of ten, but despite this the war was not going well for the South.
Following the clandestine dispatch of a few hundred additional advisors and Special Forces troops to Vietnam in the spring of 1961, the US government eventually decided to commit itself openly. Not everybody believed that the fall of Vietnam to communist rule would necessarily lead to the loss of the rest of Southeast Asia, but it was nevertheless felt that the time had come to take a firmer stand. Various proposals on the suitable composition of the US forces to be sent to Vietnam were drawn up during the summer and autumn of 1961, and many of these emphasized the importance of air support. President Diem was reluctant to request US ground combat units, but he too recognized the need for tactical aviation.
The first Vietnamese air units had been set up by the French in 1951, as an integrated part of the Army. The Không Quân Viêt Nam, the Vietnamese Air Force, usually abbreviated to VNAF, was formed on 1 July 1955. It initially consisted of 58 transport and liaison aircraft, organized into five squadrons. The 1st Fighter Squadron was created in June 1956, when twenty-three Bearcats were handed over to the VNAF by the French, and for the next few years this remained the only combat unit of the young air force, although kept at full strength by additional batches of Bearcats (for a total of sixty-nine, of which twenty-one were only used for spare parts). President Diem had also requested the French advisory team to create a B 26 squadron for his air force, but since both the French and the US advisors thought that the VNAF lacked the personnel and resources to equip and maintain a bomber unit, this request was refused.
By the late 1950s the Bearcats were becoming increasingly obsolete and worn out, and finding a suitable replacement became a priority issue. Since the Geneva Accords in effect prohibited the introduction of jet aircraft into Vietnam, the replacement would also have to be a piston-engined aircraft. After once more considering the B 26 as a possible candidate, the United States finally decided on the Skyraider, and the first of these began to replace the Bearcats from late 1960. In mid 1961, the VNAF could only muster a single combat squadron of twenty-five aircraft in the war against the Viet Cong. A second unit, the 2nd Fighter Squadron, was due to be formed with T 28s later in the year, but there was little prospect of any immediate expansion of the VNAF beyond that, although several additional Skyraider squadrons were to be formed a few years later.
This was the background to the initial deployment of US strike aircraft to South Vietnam. The USAF unit chosen for use in Vietnam was the 4400th Combat Crew Training Squadron of Tactical Air Command, also known as Project Jungle Jim. The squadron had been formed on the initiative of General Curtis E. LeMay in response to a presidential request for an increased US counter insurgency (COIN) capability - which was prompted by a Soviet pledge in January 1961 to support 'wars of liberation' - and was tasked with the development of tactics for a COIN rôle. The official date of formation was 14 April 1961, which happened to be the day on which Brigada 2506 sailed from Nicaragua for the Bay of Pigs, with the support of another classified American B 26 unit.
It was intended that the 4400th CCTS should be able to deploy