This paper focuses on unpacking the United States Air Force's (USAF) instructional system development (ISD) model as it evolved over time to its present form. In post-World War II training, the USAF was a leader in the study and use of systematic instructional design procedures, with its early efforts often coinciding with the work of the Department of Audio-Visual Instruction (DAVI) and in collaboration with the scholars who shaped both military training and the Association of Educational Communications and Technology (AECT). This paper draws from the original research on USAF training design as well as official USAF publications, inspection reports, DAVI and AECT publications, and the Air Training Command's "Instructors' Journal." This study revealed that three distinct ISD models have existed in ISD literature. As a framework for examining the evolution of the USAF ISD model, the seven attributes on idealized design posited by Smith and Boling ("Educational Technology," 49(4), 3-17, 2009) were used.