Despite the number of large-unit operations in the initial phases of American involvement, tactical operations by brigades, battalions and companies comprised the bulk of the American effort throughout the war. Since allied units were scattered widely in order to control large areas and to increase chances of finding the enemy, aggressive and competent leadership for smaller units remained essential for all tactical operations.

Operation by units smaller than the division (or even brigade) were the key to the pacification effort and the key to finding the enemy. In jungle operations, small-unit tactics were essential, for heavy vegetation and broken terrain provided ideal concealment for the enemy. If a commander expected to find the enemy, he had to disperse his subordinate units even though reinforcement became extremely difficult when contact was made with the enemy.135 The need for small unit operations also applied to mechanized infantry, and one former battalion commander stated, "As I saw the war in Vietnam, it belonged to the company commander. He was the key to success-a planner, a doer, an independent operator, and a leader of men."136

After the end of the US ground role in Vietnam, two general officers noted that they had initially thought the best combat results were obtained from larger engagements rather than smaller ones. After smaller unit operations received greater emphasis, they discovered that the number of enemy casualties increased and that the great majority of these losses came in small contacts.137 Larger unit operations, however, were necessary to provide a protective shield for smaller unit operations and to destroy large enemy concentrations.

In the initial phases of US participation, the helicopter emerged as one of the most important innovations of the war. Its great mobility and carrying capacity provided the essential ingredient for operations in the diverse terrain of Southeast Asia against the enemy's light infantry. As a carrier of supplies, ammunition, equipment and wounded personnel, its functions ranged far beyond that of simply being a combat vehicle. Only the helicopter could accomplish the variety of tactical tasks ranging from the insertion of a long-range patrol to the vertical assault of an entire division.

Employment of the helicopter enabled the free world forces to mass men and equipment in a fashion fundamentally affecting tactical methods. Helicopters could transport units to a battle area and could also enable them to maneuver or to reinforce, displace or withdraw combat power during the battle. Helicopters could also be used to concentrate forces quickly. The dominant characteristic of the development of infantry organizations and tactics during the war was the increasing application of airmobile concepts and tactics.138