03:00 PM EST, 11/08/2024 (MT Newswires) -- (Updates to add American Airlines' ( AAL ) comment in the fourth paragraph.)

The US Court of Appeals for the First Circuit on Friday upheld a lower court's ruling that blocked a joint venture between American Airlines ( AAL ) and JetBlue Airways ( JBLU ) .

Under the joint venture, called the Northeast Alliance, the two airlines effectively agreed to operate as a single carrier with respect to most of their routes in and out of New York City and Boston, according to a court filing.

The US Department of Justice and several states filed suit to enjoin the airlines from proceeding with the joint venture under alleged violations of the Sherman Act, and the district court ruled in their favor.

"We are disappointed and disagree with the First Circuit's decision. 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," American Airlines ( AAL ) said in a statement to MT Newswires. "We are reviewing the decision and considering our options."

JetBlue ( JBLU ) did not immediately reply to MT Newswires' request for comment.

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