U.S. airlines in June turned in their worst on-time performance since December, the Department of Transportation said Tuesday.
The airlines had a combined on-time arrival rate of 76.1 percent. In May, that rate was 80.5 percent. But the 19 airlines that report monthly on-time data had fewer delayed flights this June than in the same month a year ago.
The most frequent reasons for flight delays included airport congestion, equipment problems and weather.
Hawaiian Airlines had the best on-time performance in June, while Comair — a subsidiary of Delta Air Lines Inc. — had the worst.
Among legacy carriers, Houston-based Continental Airlines Inc. reported the fewest delays, and American Airlines posted the worst on-time performance.
Legacy carriers are those airlines that had a large presence in a number of regions before the industry was deregulated in 1978.
Airlines report monthly on-time data and the causes of delays and cancellations for nonstop flights to the Department of Transportation in broad categories — such as "Extreme Weather" and "National Aviation System Delay" — that were created by the airlines, industry groups, travel agents and government officials.
Delays had eased in recent months as carriers reduced flights and flew smaller planes because of fewer passengers.
A flight is considered on-time if it arrives within 15 minutes of the scheduled arrival time shown in the carriers' computerized reservations systems. Canceled and diverted flights are counted as late.
Reports of mishandled baggage fell 20 percent in June from a year ago, DOT said, but there were more complaints in June than in May. AirTran had the fewest complaints, while American Eagle Airlines — a unit of American Airlines — had the most.
DOT said overall complaints were also down from a year ago. Passengers complained most about cancellations, delays and missed connections.