Salt Lake City International Airport had the best on-time arrival and departure rates among the 32 biggest airports in the country so far this year.

The U.S. Department of Transportation says overall, more than 80 percent of the flights were on time.

Chicago's O'Hare International Airport was at the bottom of the government's list by one measure, with only 63 percent of its flights taking off on time. All the figures are for the first half of the year.

New York's LaGuardia had the worst on-time arrival rate at 58 percent.

In Salt Lake City, an industry consultant said Delta Air Lines and SkyWest Inc. deserve a lot of the credit for running a tight schedule.

"It's a good airport. But there's nothing particular to the airport itself that would be responsible for having a better on-time performance. It's the airlines," said Mike Boyd, president of BoydGroup Inc. of Evergreen, Colo.

Together, Delta and SkyWest carry about 70 percent of the passengers using the Salt Lake airport.

Weather was a culprit elsewhere, with big hub airports such as Dallas-Fort Worth International prone to thunderstorms. Salt Lake City, by contrast, received little rain this summer.

American Airlines, the nation's biggest carrier, had the worst on-time rate, at 58.8 percent. United Airlines was next at 59.3 percent.