Field studies of agricultural airplane operations indicated that airplane design parameters significantly affected aircraft productivity. Limitation of material discharge rate, while still securing uniform distribution pattern of ejected material, appeared to be a serious factor in restricting markets and holding down productivity.A computer program was written to explore possible gains from optimizing design parameters in a given market, to determine improvements which would result from extending the range of design parameters, and to study the effects of different operating procedures. The program actually “flies” an airplane through all steps of a mission. A mission is defined as a complete working day from preparation for first take-off to shutting down after last landing. All flight operations are defined in terms of airplane specifications and design parameters.Comparison of productivity and profitability of airplanes currently being used was made with paper designs, some of which incorporated features as boundary layer control and high rate material ejection. Productivity, in terms of acres covered per operating hour, and profits show definite improvements with expanded design parameters.