Costs are playing an ever-increasing role in determining what the next generation of aircraft and engines will be. In addition to deciding to what extent wing/engine integration or drag-reducing laminar flow technologies can be employed, etc., the economic impact on both aircraft operation and engines launch and development costs must be evaluated. SFC or fuel burn advantages are no longer dominant to the extent they used to be and for some apparently promising technology concepts the cost disadvantages outweigh the aerodynamic advantages when both effects are transposed into aircraft direct operating costs. In addition, a simple metric has been evolved to rank different technology concepts and prioritize them in order to help determine the most deserving technologies for scarce development funds.

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