Thousands of travelers were stranded at U.S. airports on Monday as a wave of canceled flights, many of them operated by Southwest Airlines, spoiled holiday plans and kept families from returning home.

One day after Christmas, people were sleeping on airport floors, waiting in long lines for customer service and waiting on tarmacs.

Francis Uba, a passenger at Baltimore-Washington International Airport, said the only thing they wanted was to get home.

On Monday, he and his family were told that their Southwest flight back to Columbus had been canceled. The airline rebooked them onto a Wednesday flight with no explanation.

Mr. Uba said he had spent five hours trying to find another flight and was considering renting a car in order to get back to his business.

More than 5,700 flights were delayed or canceled in the United States as of Monday afternoon. Southwest had about 700 canceled flights and 65 percent of its flights were canceled.

Southwest was experiencing disruptions as a result of the winter storms, according to a spokesman. We are stabilizing and improving our operation now that the weather is better.

The disruptions have kept many people from visiting their families over the holiday season and added to the problems caused by the cold weather.

The second leg of his trip was canceled when he arrived at the airport. He spent about nine hours in the airport on Monday.

Mr. Bae said he didn't know what to do at this point. After spending Christmas with his family, he was going to see his own for a few days. I am stranded on my own because I don't have time with any of my family.