Report: About one in five flights late

? This summer is shaping up as the worst for flight delays since 2000, when about one in five flights was late.

The gloomy picture is due to the large number of people traveling — passenger loads have returned to levels before 9-11 — and a weather pattern producing severe storms in some of the nation’s most congested airspace.

On Wednesday, storms delayed flights to New Jersey’s Newark Liberty International Airport by more than three hours. Other airports along the East Coast — in Baltimore, Washington, Boston, New York and Philadelphia — experienced delays up to an hour.

During the summer of 2000, severe thunderstorms coupled with large passenger loads and work slowdowns led to massive delays. While few experts expect this year’s problems to be as pronounced, most agree there will be significantly more delays than the previous three summers.

“Airplanes are going to be very full, airports are going to be crowded, there are going to be long lines at security,” said David Swierenga, an airline economist and president of Vienna, Va.-based AeroEcon.

Passengers know it already.

“The planes are really jammed, and service seems to be suffering,” said Ken Cahill, a traveler from Asheville, N.C., passing through Reagan Washington National Airport.

Another traveler at the airport, Don Greenberg of Cincinnati, said he’d seen problems from the increase in passengers and from lines at security checkpoints. “I travel every other week and sometimes three to four cities are delayed,” he said.

Swierenga believes 2004 will top the record 666 million airline passengers in 2000. A rebounding economy and the lowest fares in a decade have lured people back to the skies.

Through May, the percentage of late-arriving flights was up 27 percent over the first five months of 2003, reversing steady improvements in on-time performance since 2000. The Transportation Department reported about one in five flights arrived 15 minutes or more behind schedule, the threshold for a flight to be considered delayed. About one-quarter of delayed flights were over an hour late.

Bad weather is the single biggest cause of delays. Unusual weather patterns have caused a high number of severe thunderstorms in some of the country’s most congested areas — from Chicago east through the upper Midwest, the Northeast and Mid-Atlantic.