United Airlines in March landed more than 84 percent of flights on time, making it the month's most punctual major U.S. carrier

, according to FlightStats. AirTran Airways followed at nearly 83 percent. US Airways (also nearly 83 percent) placed third, followed by Alaska Airlines (82 percent) and American Airlines (81 percent). With a 68 percent March on-time arrival rate, Southwest Airlines again ranked last among the nine largest U.S. carriers, though FlightStats acknowledged the airline "disputes the accuracy of this data," derived from Federal Aviation Administration arrival figures.