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 during one of the busiest and most stressful travel stretches of the year. The cancellations and delays one day after Christmas left people sleeping on airport floors, standing in hourslong customer service lines and waiting on tarmacs for hours on end. The problems are likely to continue into Tuesday and later this week. As of Monday night, about 2,600 U.S. flights scheduled for Tuesday were canceled, including 60% percent of all Southwest flights. “The only thing we want is to get home,” said Francis Uba, who was among the frustrated passengers at Baltimore-Washington International Airport on Monday, where over 130 flights were canceled as of that evening. He and his family returned from an eight-day cruise in the Bahamas on Monday to learn that their Southwest flight back home to Columbus, Ohio, had been canceled. Uba, 60, said the airline had rebooked them onto a Wednesday flight with no explanation. Uba, who owns a health business, said he had spent five hours trying to find another flight but had not even been able to reach an airline customer service agent and was considering renting a car in order to get back to work. More than 3,800 flights in the United States — including international flights into or out of the country — had been canceled as of Monday night and more than 7,400 others had been delayed, according to FlightAware, a flight tracking service. Southwest was by far the most disrupted airline, with more than 2,800 canceled flights, about 70% of its total flights, FlightAware showed. Chris Perry, a spokesperson for Southwest, said that the airline was “experiencing disruptions across our network” as a result of the winter storms. “Our biggest issue at this time is getting our crews and our aircraft in the right places,” Perry said in an email. A statement on the airline’s website called the cancellations “unacceptable.” David Vernon, an airline analyst at the financial firm Sanford C. Bernstein, said Southwest’s network is organized in what is known as a point-to-point system, which enables higher use of planes during normal times but can cause cascading negative effects when things go wrong. “It comes down to the structure of Southwest’s network and its exposure to hard hit areas like Chicago and Denver,” he said. On Monday night, the U.S. Department of Transportation said it would look into the Southwest issue, and that it was “concerned by Southwest’s unacceptable rate of cancellations and delays.” “The department will examine whether cancellations were controllable and if Southwest is complying with its customer service plan,” the agency said in a statement. Among the hardest-hit airports were the Denver, Las Vegas, Dallas, Phoenix and Baltimore airports, all of which had more than 100 canceled departing flights as of Monday night, as did Chicago Midway International Airport. Denver alone had more than 220 canceled flights, making up nearly a quarter of its scheduled outbound trips. The disruptions have kept many people from visiting their families over the holiday season and added to the problems caused by snow, ice and frigid weather during the holiday weekend. At Austin-Bergstrom International Airport, thousands of stranded and confused passengers massed throughout the terminal in lines that snaked in all directions. One line, with no end in sight, stretched to the Southwest ticket counter, where perhaps 10 or 15 agents staffed counters as customers queued up to learn their options — if there were any. Hundreds were clustered on the level below, grouped around hundreds of bags, many of which had been dispatched back to Austin from canceled flights. Subscribe to WRAL: / wral5 Follow WRAL: Facebook: / wraltv Twitter: / wral IG: / wral About WRAL-TV: WRAL is your Raleigh, North Carolina news source. Check out our videos for the latest news in Raleigh, local sports, Raleigh weather, and more at https://WRAL.com #nationalnews #airport #southwest 00:00 Tampa International Airport 02:01 Kansas Couple stuck in Georgia 02:27 Jacksonville International Airport 02:54 NYC Couple busses to Georgia 03:48 Strangers Road trip from Arizona to Sacramento