In contrast to ROLLING THUNDER, the air campaign in Laos was driven by a straight forward military objective: to interdict the flow of men and supplies from North to South Vietnam. The effort was therefore relatively unhampered by micro-management from the top, but, on the other hand, it was marked by considerable inter- service wrangling over just who would control what, when and how. At first, TIGER HOUND was controlled by General Westmoreland's staff in Saigon, on the premise that the target area was part of the extended battlefield in South Vietnam, while the Air Force controlled STEEL TIGER and the bulk of the air assets involved. The Air Force objected to this arrangement on the basis that it violated the principle of unity of command and, in 1968, it was given control of the entire air interdiction effort against the Ho Chi Minh Trail and STEEL TIGER absorbed TIGER HOUND. A similar set of relationships came into play over North Vietnam immediately above the DMZ, which the Marines considered a part of their extended battlefield. The issue in this case was complicated by a sharp philosophical divergence between the Air Force and the Marines, who preferred to give their ground commanders direct control of Marine air. In South Vietnam, the result was an elaborate compromise in which the Marines nominally relinquished control to the Air Force under certain specific circumstances but generally retained first call on Marine aircraft. Called TALLY HO, the area above the DMZ fell under joint Air Force/Marine auspices. Like STEEL TIGER, it was exempted from the bombing halt when ROLLING THUNDER was cancelled.
In all these areas, U.S. airmen engaged in a day-in, day-out effort to staunch the southward flow of communist manpower and materiel. Though communist defenses were generally more intense in TALLY HO, particularly when a communist ground offensive was underway, the most bitterly fought campaign was in south Laos where the Air Force pulled out all the stops in an effort to make interdiction work. B-52s were thrown into the struggle, particularly in attacks on staging and storage areas in the Trail's southern termini. Secretary of Defense McNamara also ordered the Trail to be sown with air-dropped seismic detectors and listening devices, monitored from a special, computerized facility at Nakhon Phanom in Thailand, to detect truck and troop movements. The struggle followed an annual rhythm, with activity slacking off during the wet summer monsoon, then picking up to reach fever intensity between November and May as dry roads permitted trucks to move, and good flying weather helped airmen to locate them. In November of 1968, the 7th Air Force formally recognized the seasonal rhythm of the air war in southern Laos by instituting a series of annual dry monsoon campaigns under the code name COMMANDO HUNT, which continued through to the end of American involvement in the war. SAM coverage rarely intruded into STEEL TIGER, though radar-controlled AAA was common, and the Air Force made extensive use of piston-engined aircraft and multi-engined aircraft, which had less evasive capacity than fighters but a more useful load capacity.
Communist trucks moved along the Ho Chi Minh Trail almost entirely by darkness and holed up in camouflaged revetments, caves and bunkers during the day, so that the campaign developed a daily rhythm. By day, jet fighter bombers ,guided by forward air controllers (FACs) who were assigned a particular segment of the Trail, attacked road segments, river crossings and suspected storage areas. By night, a small and increasingly specialized armada came out to hunt trucks. Antiquated piston-engined A-26s and T-28s were used for a time, and C-123s and C-130s were used to drop flares for marauding fighter bombers. F-4s, working in pairs and dropping their own flares, were used with some success. It was dangerous work in which vertigo and the karst ridges and mountains of Laos, invisible in the darkness, were as much of a threat as enemy fire.