For an aircraft to be successful in the marketplace, design decisions must consider all impacts on the customer. Of particular importance is the decision with regard to potential weight increases. Since weight affects performance, and thus the customer's ""bottom line"", weight changes should be evaluated with a ""dollar based"" metric. This paper outline a framework for evaluating weight during detail design using a hypothetical study aircraft. The approach explicitly links the decisions of customers and original equipment manufacturers so the effects of a weight change can be better understood. Airline operations are emphasized, but the approach can be extended to other uses. Both aircraft performance and data provided are hypothetical and do not reflect current or future aircraft.