A federal decide on Friday ordered American Airways and JetBlue Airways to finish their partnership within the Northeast, a win for the Justice Division after it sued to undo the alliance arguing it was anti-competitive.

The lawsuit, filed in September 2021, alleged that the airways’ alliance was successfully a merger that may harm customers by driving up fares. The trial started a yr later in Boston and wrapped up in December.

Fort Price, Texas-based American Airways and New York-based JetBlue Airways argued they wanted the so-called Northeast Alliance to higher compete with different massive carriers Delta Air Traces and United Airways in congested airports within the area.

“No matter the advantages to American and JetBlue of changing into extra highly effective—within the northeast typically or of their shared rivalry with Delta—such advantages come up from a unadorned settlement to not compete with each other,” U.S. District Choose Leo Sorokin wrote in his ruling. “Such a pact is simply the type of ‘unreasonable restraint on commerce’ the Sherman Act was designed to stop.”

He ordered the airways to finish the partnership 30 days after the ruling. The carriers are more likely to problem the choice. The airways did not instantly remark.

Undoing the partnership can be troublesome, particularly throughout the peak summer season journey season, which airways have already bought tickets for.

JetBlue and American will not be allowed to coordinate fares underneath the partnership, which was permitted within the closing days of the Trump administration in 2021 and has since expanded.

JetBlue had beforehand warned in a securities submitting {that a} ruling in opposition to the NEA “might have an adversarial impression on our enterprise, monetary situation, and outcomes of operations.

“Moreover, we’re incurring prices related to implementing operational and advertising and marketing components of the NEA, which might not be recoverable if we have been required to unwind all or a portion of the NEA,” the corporate stated.

The Justice Division did not instantly reply to a request for remark.

The division individually in March filed an antitrust lawsuit to dam JetBlue’s proposed acquisition of funds service Spirit Airways, arguing the deal would drive up fares, “harming cost-conscious fliers most acutely.”

That mixture faces a excessive hurdle for approval by the Biden administration, which has vowed to take a tough line in opposition to what it views as anticompetitive offers.