Southwest Airlines regained the top spot among major carriers in the U.S. Department of Transportation's on-time performance rankings

by posting an 81 percent punctuality rate during August. Northwest placed second while AirTran and Alaska finished near the bottom. Also among majors in August, Northwest, Continental and JetBlue had the lowest mishandled baggage ratios while US Airways had the highest. US Airways also drew the worst customer complaint ratio; Southwest had the best.