Hartsfield-Jackson International Airport's on-time performance declined in May, dropping the airport to 26th among the nation's major airports, down from No. 6 just a year earlier.
About 69.8 percent of flights arrived on time at Hartsfield-Jackson in May, down from 84.32 percent in the same month of 2008.
Among airlines, Atlanta-based Delta ranked No. 14 for on-time performance, with 77.4 percent of flights arriving on time in May.
At the bottom of the rankings were Delta regional subsidiary Comair at No. 19; Atlanta-based Atlantic Southeast Airlines, a Delta partner, at No. 18; and AirTran Airways, which has its largest hub in Atlanta, at No. 17. Delta's merger partner Northwest Airlines took the No. 7 spot.
Comair also had the two most frequently delayed flights in the nation in May: a flight from New York's John F. Kennedy International to Minneapolis-St. Paul (late 96.8 percent of the time) and a flight from Kansas City to New York LaGuardia (late 92 percent of the time). An Atlantic Southeast Airlines flight from Baton Rouge to Atlanta was late 88.5 percent of the time.
Comair also had the highest rate of chronically-delayed flights, with 6.5 percent of its flights running late at least 70 percent of the time.
The list of the longest tarmac delays included a Delta flight from New York JFK to Cincinnati, delayed on the tarmac for nearly five hours.
The report also showed AirTran had the best baggage handling performance among airlines ranked. Delta performed worst in the complaints category, with the highest rate of consumer complaints reported to the U.S. Department of Transportation.
