Stocks finished lower Friday with volume trailing off, according to preliminary data. For the day, the Nasdaq fell 0.6%, while the S&P 500 dropped 0.7% and the Dow Jones industrial average 0.8%. Airlines were the best-performing industry group, up about 1.7% on the day. The group was recovering after being hammered earlier this week. Alaska Air Group (ALK) rose nearly 3% after finding support at its 200-day moving average.