More flights are arriving on time but consumer complaints about the airlines have risen sharply.

The U.S. Department of Transportation said Thursday that the nation’s leading carriers posted an on-time rate of 80.3 percent in August. That was better than the 78.1 percent mark in July and 77.7 percent the previous August.

Delta Air Lines had the best on-time rate, 85.5 percent, followed by Alaska Airlines at 82.9 percent.

Spirit Airlines rated last, with an on-time rate of 63.7 percent. JetBlue Airways was next to last at 74 percent. The government counts a flight as on time if it arrives within 14 minutes of schedule.

Complaints most frequently concern delayed flights, but baggage or ticketing problems, customer service and fares are also included.

Two domestic flights in August were stuck on the tarmac longer than three hours, which could trigger violations of federal rules. One was a Delta flight delayed at Orlando, Florida, and the other was a PSA Airlines flight held up at Charlotte, North Carolina. PSA operates US Airways Express flights.

Consumers filed 1,633 complaints about U.S. airlines with the government, up from 1,107 a year earlier. Spirit had the highest complaint rate by a wide margin. Consumers were nearly twice as likely to complain about Spirit as about Frontier Airlines, the carrier with the second-worst record. Both airlines advertise low fares but charge more fees than most other carriers.

Many more travelers complain directly to the airlines, so the government report does not fully capture consumer displeasure. The CEO of Frontier Airlines estimated that his company gets 30 complaints for every one filed with the government.

Rank Airline On-Time Rating
1 Delta Air Lines 85.5%
2 Alaska Airlines 82.9%
3 Hawaiian Airlines 81.5%
4 ExpressJet 80.8%
5 Virgin America 80.6%
6 American and US Airways 80.6%
7 Envoy Air 80.5%
8 SkyWest Airlines 79.8%
9 Southwest Airlines 79.5%
10 United Airlines 78.8%
11 Frontier Airlines 77.1%
12 JetBlue Airways 74%
13 Spirit Airlines 63.7%

Total for all reporting airlines: 80.3 percent
Source: U.S. Department of Transportation

The Department of Transportation report can be found at http://1.usa.gov/1NpZ2YP

Photo Credit: Delta topped all other U.S. airlines in on-time performance in August. Delta Air Lines