American Airlines has ended partnership talks with carrier JetBlue Airways and filed a lawsuit seeking damages after the collapse of the Northeast Alliance (NEA), Vice Chair Steve Johnson said in a letter to employees.

American Airlines was in talks with JetBlue for a partnership to strengthen its network and loyalty program.

"Ultimately, we were unable to agree on a construct that preserved the benefits of the partnership we envisioned, made sense operationally or financially," American Airlines' Johnson said in the letter Monday.

In February, JetBlue said it was still in talks with multiple airlines to establish a partnership and is willing to allocate more funds to get a deal done.

The biggest benefit of a partnership would be improving the utility of JetBlue's loyalty points for customers which trails multiple competitors.

The NEA was announced in July 2020 and received approval from the U.S. Transportation Department just days before the end of Republican President Donald Trump's first term in January 2021.

The alliance allowed the two carriers to coordinate flights and share revenue, forming a key part of American Airlines' strategy to gain ground in the New York market, where it had been operating at a loss.

The NEA was dissolved after a non-jury trial in May 2023 concluded that the partnership violated federal antitrust law, a ruling later upheld by a U.S. appeals court.

American Airlines said on Monday that it filed a lawsuit to recover money owed by JetBlue following the unwinding of the NEA.

The Texas-based firm is seeking monetary relief of more than $1 million, excluding attorney fees and costs from JetBlue, according to the lawsuit filed in a Texas court.

JetBlue did not immediately respond to a request for comment.