JetBlue Airways said Wednesday that it will terminate its partnership in the northeast U.S. with American Airlines after a federal judge ruled to block the agreement, as the New York airline focuses on its acquisition of Spirit Airlines.

American said last month that it would challenge the ruling against the JetBlue partnership, but New York-based JetBlue said Wednesday it would not appeal the decision.

“Despite our deep conviction in the procompetitive benefits of the NEA, after much consideration, JetBlue has made the difficult decision not to appeal the court’s determination that the NEA cannot continue as currently crafted,” JetBlue said in a statement.

It said it has started terminating the agreement, “a wind down process that will take place over the coming months.” JetBlue said it will “now turn even more focus to our proposed combination with Spirit.”

JetBlue’s deal to buy Spirit came together after JetBlue and American launched a partnership in the Northeast. The so-called Northeast Alliance, approved during the last days of the Trump administration, allows the two carriers to share passengers and revenue and to coordinate schedules.

But a federal judge ruled in May that that partnership was anticompetitive, ordering the two airlines to undo the alliance.

American Airlines said Wednesday that it will still appeal the ruling.

“JetBlue has been a great partner, and we will continue to work with them to ensure our mutual customers can travel seamlessly without disruption to their travel plans,” American said in a statement on its website.

A spokesman for the airline did not immediately say how American could salvage the deal if JetBlue plans to begin unwinding it.

“We, of course, respect JetBlue’s decision to focus on its other antitrust and regulatory challenges.”