Illustrates estimation of support investment costs and recurring operations and support costs through a Model for estimating Aircraft Cost of Ownership (MACO), which also provides a framework for future research. MACO is an outgrowth of an earlier evaluation of the strengths and weaknesses of the most widely used aircraft life cycle cost models. It combines new algorithms for major, maintenance-related costs with formulas drawn from existing models for other cost elements. MACO relates a full set of ownership cost elements to component level reliability and maintainability characteristics and to aircraft design, operations, logistics, and deployment parameters, although the MACO equations would have to be reorganized before they could be used to estimate costs according to the cost structure of the latest Cost Analysis Improvement Group guide. MACO computes resource quantities in units that can be related directly to Air Force programming categories, including base maintenance manning (by work center), depot manning, and recoverable spares inventory levels. Output and input parameters accommodate annual changes in system parameters and operating conditions such as component reliability and aircraft inventory size and activity rates.