 Complete the following phrase:  The squadron was activated in 1967, and took over the DeHavilland Canada C-7A Caribou aircraft operated by the 57th Aviation Company U.S. Army and its tactical airlift mission in South Vietnam. It operated from several locations in addition to its primary base at Vung Tau Airfield. The 535th airlifted routine cargo and passengers, provided support for Army special forces and radio relay for ground units, airdropped troops and cargo, performed emergency resupply and medical evacuation, and flew other combat airlift missions. It earned a Navy Presidential Unit Citation, as well as an Air Force Presidential Unit Citation for airlift support of 