Southwest Flips on Big Three Airlines in Cartel Case

Southwest Airlines Co. settled a multi-district cartel case for $15 million and a promise to help the plaintiffs make their case against the three remaining defendants: American Airlines Group Inc., Delta Air Lines Inc., and United Continental Holdings Inc.

Southwest, as the first settling defendant, is paying relatively little in cash to exit the lawsuit. But the settlement also involves Southwest turning over “a full account of facts then known to Southwest that are relevant to the claims asserted in the action,” according to the plaintiff’s lawyers.

The airline said Jan. 2 that it settled the class-action consumer claims to ...