The U.S. Air Force has a goal of reducing the life cycle operating and support (O&S) costs of the F-35A. Maintenance manpower is a significant driver of O&S costs, and consolidation and reorganization of career fields could reduce manpower and training costs. The authors of this report evaluate the costs and benefits of six F-35A maintenance manpower force structures in the U.S. Air Force that merge maintenance career fields in different ways.