From Philadelphia to Cincinnati, thousands of holiday travelers spent much of their Christmas weekend sleeping in airport terminals and rearranging flight schedules because of a confluence of poor weather, labor unrest and computer meltdowns.

The problems began on Wednesday and Thursday, when a winter storm buffeted the middle swath of the country, and continued through yesterday.

Travelers using US Airways, the financially troubled carrier, were perhaps the most affected. The airline canceled 65 flights on Thursday, 176 on Friday and 143 yesterday. The airline said flight attendants across its network and baggage handlers in Philadelphia had called in sick in unusually high numbers. Union representatives for both sets of workers denied there had been any job action authorized.

Yesterday, the travel plans of 30,000 passengers in 119 cities were disrupted when Comair, a subsidiary of Delta Air Lines, canceled all of its 1,100 flights after its computer system crashed.

In Philadelphia, the problems, including a pileup of an estimated 8,000 to 10,000 luggage items, were so severe that the United States transportation secretary personally intervened.
The secretary, Norman Y. Mineta, was on the telephone with his aides “well into the midnight hours” as he tried to get an account of the problems at US Airways, said a spokesman for the Department of Transportation.
“The secretary was quite concerned last night when he saw that the Philadelphia airport had turned into a huge hotel for people who were stranded by the thousands there, and at other airports in the Northeast, because of problems with baggage handling and getting flights moving,” the spokesman, Robert R. Johnson, said yesterday.
Mr. Johnson added, “We will, as the week unfolds, press for answers as to what really went on here.”

Travelers said they were awestruck by the chaotic situation at the airport.
“Even post-9/11 I’ve never seen it this bad,” said Rodney Gibson IV, 29, a graduate business student at the University of Pennsylvania. “I’ve never seen anything like it before.”
Mr. Gibson, who took a Northwest Airlines flight from Philadelphia to San Jose, Calif., on Friday morning, said the lines around the airport seemed interminable.
“The line went out the doors,” he said in a telephone interview. “It did the whole accordion deal, zigzagging the normal way, and then out the door and onto the sidewalks.”

Several of the airport’s terminals resembled barracks as entire families installed themselves for overnight stays. Airport workers handed out coffee, hot chocolate, water, snacks, pillows and blankets, said Mark Pesce, a spokesman for the city-owned airport. Workers at the Philadelphia Airport Marriott, whose 414 rooms quickly filled, gave out toothbrushes, razors and toiletries.

In September, US Airways, the nation’s seventh-largest airline, filed for bankruptcy protection for the second time in three years. The airline has won wage concessions from most of its unions, with the baggage handlers a notable exception.
“We have no reason to believe an organized job action has taken place,” Amy Kudwa, a spokeswoman for the airline, based in Arlington, Va., said yesterday. But she added that the airline received an “unusually high number of sick calls” from baggage handlers in Philadelphia and from flight attendants.

The airline flew five extra, unscheduled flights from Philadelphia to Charlotte, N.C., on Friday, carrying only luggage that was to be sorted and delivered, Ms. Kudwa said. The last flight left at 10 p.m. Friday, she said, and additional luggage was being trucked from Philadelphia to various airports. Managers were even called to fill in as flight attendants.
“We are embarrassed by the situation, especially given the holidays and how important travel is to our customers at this time of the year,” US Airways said in a statement yesterday. The airline also said that its efforts to recover from the severe weather “were complicated when some of our employees chose to call in sick at record numbers over the weekend.”

An aviation analyst and consultant, Robert W. Mann, said the problems could mark the start of a downward spiral as dispirited workers make it harder for US Airways to hold on to customers.
Mr. Mann said he believed that workers had essentially organized a work stoppage.
“It is a manifestation of how frustrated these employee groups are,” Mr. Mann said. “But in saying that, these sorts of disruptions do nothing else but accelerate the date of the final paycheck.”
He said the damage to customer satisfaction could be irreparable. “You’re going to have customers who were willing to give them a try but, having been treated in this way over the holiday period, are clearly going to vow never to fly them again,” he said.

Spokesmen for the two unions said they were not aware of any sickout by their members. “I am totally unaware of any action like that,” said David Kameras of the Association of Flight Attendants, which merged this year with the Communications Workers of America.

A spokesman for the International Association of Machinists and Aerospace Workers, which represents the baggage handlers, also denied a sickout had occurred. “I’m not aware of anything unusual occurring in Philadelphia and the union has certainly not called for any type of job action at US Airways,” said Joseph Tiberi, the spokesman.

The cancellation of all flights of Comair occurred after its computer system was overwhelmed as workers tried to arrange new flights after the Midwest storm.
“The computer system used to assign the flight crews became inoperative,” said Tracey Bowen, a spokeswoman for Delta, which is based in Atlanta.

At La Guardia Airport, hundreds of stranded Comair travelers waited in line for hours, all trying to find alternate flights to their destinations.
“They haven’t explained a thing to us,” said Sylvia Gubacsi, 63, of Hilton Head, S.C., who was trying to return home from a holiday visit to her daughter in Manhattan.