A plan by JetBlue Airways to sign a domestic partnership with another airline faces opposition from its pilot union, which has warned the move could "fundamentally reshape" the U.S. carrier and impact the future of its workers.

JetBlue is reportedly discussing a potential partnership with United Airlines after its planned Northeast Alliance with American Airlines failed. The Department of Justice sued to block the alliance between the two airlines in 2021, characterizing it as anti-competitive.

American Airlines on Monday sued JetBlue Airways in the Business Court of Texas to recover funds that JetBlue allegedly owes from the failed Northeast Alliance partnership effort.