WASHINGTON — After the crammed parking lot, the amusement-park-length check-in lines, security procedures that require all but a striptease, flights that are jam-packed, if they're not delayed or canceled — after all that comes baggage claim, where the maddening odyssey of modern air travel is supposed to end but often just gets worse.

More than 1 million pieces of luggage were lost, damaged, delayed or pilfered by U.S. airlines from May to July, according to data from the Bureau of Transportation Statistics. June and July ranked among the 20 worst months for mishandled baggage in 20 years.

The shoddy service is the crest of five years of steady deterioration in the ability of major airlines to deliver a checked bag. In 2002, 3.84 reports of mishandled bags were filed per 1,000 passengers. In July, the figure was 7.93.

Frustration has mounted to the point that even a well-traveled congressman, Rep. Bob Filner, D-Calif., is alleged to have barged, screaming, into a United Airlines baggage claim office at Washington's Dulles International Airport and shoved a clerk, leading to a misdemeanor assault charge. Filner disputes the charge and is due in court today.

His explanation summed up the feelings of many fliers: "I was tired after a delayed flight and frustrated by the subsequent further delay of the entire flight's baggage," he said after the August incident.

How did it come to this?

Airline representatives and analysts cite a variety of factors. Restrictions on gels and liquids in August 2006 have led to a surge in the number of checked bags. Airlines aggressively slashed jobs after the industry's historic downturn several years ago, leaving fewer employees to handle baggage and customer service issues.

An underlying problem is the major carriers' reliance on hubs, which are transfer points for connecting flights, increasing the probability of luggage getting misplaced or not making the next flight in time.

Even the size of airplanes is being blamed. Carriers have increased the number of regional jets in their fleets, and the smaller planes have weight restrictions that limit the amount of luggage they can carry.

The airline industry attributes the baggage problem in large part to delays caused by weather and an antiquated air traffic control system. The system limits the number of planes controllers can safely move through the sky.

"The primary reason behind mishandled bags is delayed and misconnected flights," said David A. Castelveter, a spokesman for the Air Transport Association, which represents the major U.S. airlines. "And we're seeing record delays this summer. ... No airline tries to (lose bags). ... The carriers are trying the best they can given the existing situation."

Analysts say the industry's problems are not likely to be resolved soon, setting the stage for more aggravation, especially during the holiday travel season.