The RAAF began its service in the Vietnam War on 8 August 1964 when three Caribou aircraft of the RAAF Transport Flight Vietnam landed at Vung Tau. The flight's remaining three aircraft arrived on 29 August; in the meantime two Caribous carried out the RAAF's first operation in Vietnam when they flew supplies to Pleiku. On 1 June 1966 the flight, its status raised, was renamed No. 35 (Transport) Squadron. For many veterans, however, the squadron will always be remembered as 'Wallaby Airlines'.
The bulk of the 35 Squadron's operations in Vietnam were known as 'milk runs' - routine, and by implication, relatively safe flights - one to the north and one to the south, on alternate days for six days a week to drop supplies at American special forces camps and to members of the Australian Army Training Team Vietnam across the Central Highlands. Coupled with this already demanding workload, 35 Squadron routinely carried out wide-ranging unscheduled daily tasks, allocated at short notice, including transporting military and civilian passengers, medical evacuations and delivering mail or general cargo (food, fuel, livestock, ammunition, spare parts.)
Benign though they sound, 'milk runs' involved certain dangers. Airfields at special forces outposts, where the Caribous often landed, were usually outside the camp's perimeter. Attacks on the aircraft in the dangerous moments of take-off and landing were always possible, but even where the enemy was absent the airfields' very location and condition could prove hazardous. For 35 Squadron pilots there was little margin for error, some airstrips were just a few metres longer than the minimum needed for a Caribou to take off. Others eroded under the flooding monsoon rains and more than one 35 Squadron Caribou crashed on these remote landing strips. After 1966 the squadron's workload increased further when Luscombe Field was opened at Nui Dat. Now the Australian Task Force base was part of the Caribous' regular run and work with the 1st Australian Task Force became a regular feature of the squadrons' operations.