U.S. carriers in May achieved an aggregate on-time performance of 78.3 percent, worse than April 2006 (78.4 percent) and May 2005 (83.7 percent)

, according to the latest U.S. Department of Transportation statistics. Northwest Airlines was most punctual among major U.S. carriers, while Continental Airlines and United Airlines were the least. Meanwhile, American Airlines and US Airways elicited the most complaints as a percentage of total enplanements while Southwest Airlines had the fewest.