In the past 50 years, the U.S. Department of Defense has pursued numerous joint aircraft programs, the largest and most recent of which is the F-35 Joint Strike Fighter (JSF). Joint aircraft programs are thought to reduce Life Cycle Cost (LCC) by eliminating duplicate research, development, test, and evaluation efforts and by realizing economies of scale in procurement, operations, and support. But the need to accommodate different service requirements in a single design or common design family can lead to greater program complexity, increased technical risk, and common functionality or increased weight in excess of that needed for some variants, potentially leading to higher overall cost, despite these efficiencies. To help Air Force leaders (and acquisition decisionmakers in general) select an appropriate acquisition strategy for future combat aircraft, this report analyzes the costs and savings of joint aircraft acquisition programs. The project team examined whether historical joint aircraft programs have saved |