Economics of scale have to be distinguished from economies of scope. The latter refer to the lowering of costs that a firm often experiences when it produces two or more products together father than each alone. A smaller commuter airline, For example, can profitably extend into providing cargo services, thereby lowering the cost of each operation alone. Another example is provided by a firm that produces a second product in order to use the by-products (which otherwise the firm had to dispose of at a cost) arising from the production of the its product line such economies of scope.