A federal judge rejected a bid by the four largest U.S. airlines to dismiss nationwide antitrust litigation by passengers who accused them of conspiring to raise fares by keeping seating capacity artificially low.

In a decision late Friday afternoon, U.S. District Judge Colleen Kollar-Kotelly said she could "reasonably infer the existence of a conspiracy" among American Airlines Group Inc , Delta Air Lines Inc, Southwest Airlines Co and United Continental Holdings Inc to fix prices.

Kollar-Kotelly, who sits in Washington, D.C., did not rule on the merits of the proposed class-action case, which combines 105 lawsuits filed around the country and seeks triple damages.