The US Supreme Court has declined to hear a case brought by Boeing, in which the company requested blocking a Southwest Airlines Pilot Association’s (SWAPA) lawsuit over inadequate training for the B737 MAX.

Boeing said it should not be subject to the lawsuit because the Railway Labor Act should preempt the dispute (as it generally does over contracts in the airline sector). While lower courts in Texas agreed with the manufacturer, the Supreme Court of Texas reversed the decision, allowing SWAPA’s fraud and negligence suit against Boeing to move forward.

After that, Boeing asked the Supreme Court of the United States to intervene and reverse the Texas court’s decision, arguing that the ruling was contrary to the analysis of the state’s previous courts, and that a different interpretation of the same federal law would “frustrate Congress’ efforts to create a uniform nationwide system for adjudicating labor disputes.”

Media outlets LAW 360 and Courthouse News Services recounted that SWAPA’s lawsuit arose after two B737 MAX crashes in 2018 and 2019. The union argued that years before these disasters, Boeing had inserted itself into the union’s negotiations with Southwest assuring that the aircraft family was simply a “more fuel efficient” version compared to the earlier Next-Generation family that was already in the airline’s fleet, so they would not need more training.

The union said it relied on those misrepresentations when agreeing to a contract with Southwest in 2016, ultimately leaving pilots grounded in 2019 after the MAX type was grounded globally for 20 months, costing pilots wages and the union dues.

Neither SWAPA nor Boeing were immediately available for comment at the time of going to press.

Southwest Airlines operates a fleet of 309 B737-700s, 197 B737-800s, and 304 B737-8s.