This study provides a preliminary assessment of the potential benefits of applying unsteady separation control to transport aircraft. Estimates are given for some of the costs associated with a specific application to high-lift systems. High-leverage areas for future research were identified during the course of the study. The study was conducted in three phases. Phase 1 consisted of a coarse screening of potential applications within the aerodynamics discipline. Potential benefits were identified and in some cases quantified in a preliminary way. Phase 2 concentrated on the application to the wing high-lift system, deemed to have the greatest potential benefit for commercial transports. A team of experts, including other disciplines (i.e. hydraulic, mechanical, and electrical systems, structures, configurations, manufacturing, and finance), assessed the feasibility, benefits, and costs to arrive at estimates of net benefits. In both phases of the study, areas of concern and areas for future research were identified. In phase 3 of this study, the high-leverage areas for future research were prioritized as a guide for future efforts aimed at the application of active flow control to commercial transport aircraft.McLean, J. D. and Crouch, J. D. and Stoner, R. C. and Sakurai, S. and Seidel, G. E. and Feifel, W. M. and Rush, H. M.Langley Research CenterTRANSPORT AIRCRAFT; ACTIVE CONTROL; COMMERCIAL AIRCRAFT; SEPARATED FLOW; FEASIBILITY ANALYSIS; AIRCRAFT CONTROL; COST ESTIMATES; COST ANALYSIS; LIFT; AIRFOILS; FLOW DISTRIBUTION...