The Supreme Court won't hear American Airlines' appeal of the decision that broke up its short-lived Northeast Alliance with JetBlue in 2023.
The decision, announced by the court on Monday, means that the trial court ruling of district court judge Leo Sorokin will stand.
Siding with antitrust regulators at the Justice Department, Sorokin concluded that the alliance, under which American and JetBlue jointly scheduled flights and split revenue on most of their operations out of Boston, Newark, New York LaGuardia and New York JFK airports, harmed competition by turning competitors into partners in the Northeast.
JetBlue quickly moved on from the partnership, and more recently announced a loyalty program partnership with United, which will serve as more limited alternative to the Northeast Alliance. But American has sought to have the decision overturned in hopes of preserving the right to enter future partnerships similar in nature to the Northeast Alliance.
However, in November, the U.S. First Circuit of Appeals in Boston determined that American had failed to make its case that Sorokin's ruling was on flawed legal grounds, nor did the airline dispel Sorokin's conclusion that the Northeast Alliance was harmful to competition.
The Supreme Court's decision not to hear the case makes that appellate decision the last word.
In a statement Monday, American said it is disappointed, but remains committed to growing its network with its own flying and with partnerships.
"The Northeast Alliance was designed to increase competition and expand customer options in the Northeast, which it clearly did during the time it was allowed to operate," the airline said.