Falling aluminum prices dragged down profit and revenue at Alcoa Inc., contributing to third-quarter results that fell short of Wall Street expectations. Alcoa has been reducing its vulnerability to low commodity prices by closing smelters and cutting costs in its mining and refining business. Excluding restructuring costs and other items, Alcoa said adjusted earnings were 7 cents per share. CEO Klaus Kleinfeld said the results, while down from a year ago, were encouraging given the volatile global economy, concern about the economy in China and developing countries, and weak aluminum prices. The company has announced recent contracts to supply plane manufacturers Airbus and Lockheed with parts made from high-tech materials such as titanium.