Weather disruptions linger for US flights, especially Southwest Airlines

Weather-related flight cancellations and delays that snarled US commercial air traffic over the holiday weekend dragged on through Monday, with the Southwest Airlines accounting for the bulk of the lingering disruptions a day after Christmas.

More than 3,800 US airline flights were cancelled on Monday — including 2,800 operated by Southwest, or nearly 70 per cent of the carrier's total scheduled for the day — according to the flight tracking service FlightAware.

Delays were reported for more than 7,100 US flight departures and arrivals overall, with several hundred by Southwest.

"Challenges are impacting our customers and employees in a significant way that is unacceptable," the airline said in a statement, citing "consecutive days of extreme winter weather".

The Dallas-based airline — one of the world's largest low-cost carriers — said it anticipated that the disruptions would continue in the days heading into the New Year holiday travel period at the end of this week.

Commercial airline traffic has been upended since last week, as an Arctic blast coupled with a massive winter storm (dubbed Elliott) took shape over the Midwest and swept over much of the United States in the lead-up to the Christmas holiday weekend.

The resulting surge in cancellations and delays — coupled with long lines and missing luggage at airports — spoiled wintertime vacation plans for countless US airline customers, during one of the busiest travel periods of the year.

Late on Monday, the US Transportation Department said that it would examine the large number of Southwest Airlines cancelled and delayed flights in recent days to determine if they were in the airline's control, calling them "unacceptable".

Kyle Goeke, 29, said that he would be stuck in Seattle for days after Alaska Airlines cancelled his flight (scheduled for early Monday) from Seattle to Missoula, Montana.

He had already travelled from Washington, DC to Seattle late on Sunday, and said he hadn't slept at all at night, forced instead to make lodging arrangements in Seattle.

"Luckily, I have a friend here in this city to help me out, many others are just left by themselves," he told Reuters.

Many would-be passengers took to social media to express their frustration and to try to get a response from the airlines.

David Sharp said on Twitter that his Southwest Airlines flight from Denver to St Louis was cancelled, and that the next flight was not available for another two days. He said he would rent a car and drive to his destination.

• US: Airlines cancel thousands of flights over winter storm