Rows of Southwest planes parked in California as thousands of flights cancelled

Thousands of Southwest Airlines flights have been cancelled across the US during one of the busiest travel periods of the year.

Passengers have been stranded at airports over the Christmas period because of the disruption, which Southwest say has been caused by staffing issues.

In a statement, the airline admitted it was 'unacceptable'.

The US Department of Transportation said it was 'concerned by Southwest's unacceptable rate of cancellations and delays [and] reports of a lack of prompt customer service.'

The disruption comes amid wider travel chaos caused by extreme winter weather across the country.

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