WASHINGTON — Transportation Department data appears to contradict the agency's own finding earlier this week that the nation's largest airline recently improved the on-time performance of chronically delayed flights.

American Airlines operated two flights that arrived late at least 70 percent of the time throughout the first nine months of this year, according to data analyzed by The Associated Press. Under a government plan, the airline faced a total of $50,000 in fines.

The Transportation Department identified dozens of chronically delayed flights earlier this year and said carriers that did not improve in the third quarter would face fines of up to $25,000 per violation.

On Monday, Secretary of Transportation Mary Peters said the six airlines operating 25 chronically delayed flights in the first half of 2007 improved their performance in the third quarter, thereby avoiding any fines.

But two American Airlines flights — one from New Jersey's Newark Liberty International Airport to Chicago's O'Hare International and another from Miami International to John F. Kennedy International in New York — arrived at least 15 minutes late more than 70 percent of the time in each of the first three quarters of 2007, according to Transportation Department data obtained by The Associated Press.