1961 To 1968
In April 1961, the PEO was upgraded to a Military Assistance Advisory Group (MAAG), and its members were allowed to wear uniforms. The MAAG was withdrawn in 1962 under the terms of the Geneva Agreement, which was supposed to neutralize Laos. Because the North Vietnamese did not respect the withdrawal requirement, the United States stepped up military aid to the Lao Government, but avoided sending ground troops into Laos, which would have violated the agreement.
As part of this effort, United States Central Intelligence Agency (CIA) personnel operating from a base at Udon Thani, Thailand, took over the support of between 30,000 and 36,000 irregulars, including Hmong guerrillas who bore the brunt of the fighting in northern Laos. A CIA-chartered airline, Air America, dropped rice and ammunition from its C-46s and C-47s to isolated Hmong outposts, which were sometimes behind enemy lines. A variety of short takeoff and landing aircraft used dirt airstrips carved out of the jungle by the Hmong. The irregulars, who became known as the Secret Army, were instrumental in helping to rescue a large number of United States airmen who were shot down over Laos. By this time, Hmong leader Vang Pao had risen to the rank of general in the Royal Lao Army and commanded the Second Military Region.
In October 1964, in response to an offensive by the Pathet Lao and North Vietnamese to expel the Neutralists from the Plain of Jars, the United States began providing air support against Pathet Lao positions and North Vietnamese supply lines. However, it was not until March 1966 at Phoukout, northwest of the Plain of Jars, that the Pathet Lao started to win major battles against the Royal Lao Army. In July 1966, the Pathet Lao won another major battle in the Nambak Valley in northern Louangphrabang Province by overrunning a Royal Lao Army base and inflicting heavy casualties. These victories gave the Pathet Lao new momentum in the war for control of Laos.
Meanwhile, in southern Laos, where the North Vietnamese had been working steadily every dry season to expand the Ho Chi Minh Trail leading into South Vietnam, the intensity of the air war also grew. The air war in Laos operated under a complicated command and control system that involved the United States embassy in Vientiane, the Military Assistance Command Vietnam in Saigon, Royal Thai air bases in Thailand, the commander in chief Pacific in Honolulu, and sometimes even the White House. The United States ambassador in Vientiane had the final say on target selection, using criteria that included: the distance of targets from civilian habitations and the types of ordnance to be expended. The ambassador also was to keep the Lao Government informed so as to avoid, or at least minimize, the latter's embarrassment vis-à-vis the British and Soviet embassies in Vientiane and the heads of the Indian, Canadian, and Polish delegations to the International Control Commission who were jointly responsible for enforcing the 1962 Declaration on the Neutrality of Laos signed in Geneva.