Using the planning and management processes in Army aviation maintenance, the authors examine how the Department of Defense (DOD) adjusts resource requirements in response to input price changes. The report is based on an extensive literature survey and several hundred interviews conducted during 1977-1979. Because defense activities are dynamic, many of the specific problems of Army aviation maintenance have changed since the period of this report. The study does not seek to solve specific problems in Army aviation maintenance, however, or even to focus exclusively on Army aviation maintenance itself. It addresses a problem that has persisted over the entire period since World War II — DOD's reluctance to recognize changing input prices and respond accordingly. The report offers no specific policy recommendations; rather it aims to provide a better understanding of how DOD's planning and management processes work, to provide a foundation upon which future work can build to define policy options that improve these processes.