U.S. airlines on schedule slightly more often in December

The U.S. Department of Transportation said Thursday that 77.8 percent of domestic flights in December arrived within 15 minutes of schedule — on time, according to the government.

Passengers on 14 December flights, including four operated by American Airlines, were stuck on the ground longer than allowed by federal rules.

Spirit, a discount airline that features low fares but charges more fees than most carriers, had the highest complaint rate, more than twice as high as its nearest rival, Frontier Airlines, another budget airline.

The on-time figures covered the 13 largest U.S. carriers, including regional airlines that operate flights using smaller planes for American, Delta and United.