The prototype and development aircraft were involved in an intensive operational testing program, along with the first C-141 to be delivered to MATS (63-8078) on 19 October 1964 to the 1707th Air Transport Wing, Heavy (Training), Tinker Air Force Base, Oklahoma. Following the satisfactory completion of civil testing, a Federal Aviation Authority (FAA) type certificate was awarded to the C-141 on 29 January 1965. The first delivery to an operational unit (63-8088) was conducted on 23 April 1965 to the 44th Air Transport Squadron, 1501st Air Transport Wing, Travis Air Force Base, California.