Southwest Airlines is being sued after Christmas operational meltdown

(CNN) — Southwest Airlines is being sued over its massive Christmas meltdown.

A passenger suing the airline says it violated federal law by offering credit for a future flight instead of a refund for cancelled flights.

A federal judge in Louisiana has been asked to certify the lawsuit as a class action to include other passengers. No comment yet from Southwest.

Meanwhile, The Transportation Department is investigating the airline’s “Operational Meltdown” that forced tens of thousands of flights to be canceled during some of the busiest travel days of the year.