Five carriers—American, Delta, JetBlue, Southwest and United Airlines—and lobbying group Airlines for America (A4A) filed a lawsuit with the U.S. Court of Appeals for the 5th Circuit on Tuesday, arguing parts of a DOT mandate issued by the Biden administration last year were “unlawful.” 

The rule established standards for airlines on accommodating passengers with wheelchairs, including penalties for airlines that lose or damage mobility aids and improvements on how to board wheelchair users on aircrafts.

DOT claimed its mandate provided the largest expansion of rights for passengers who use wheelchairs since 2008. The rule states that any damage to or delay in returning a wheelchair is an automatic violation of the Air Carrier Access Act, which prohibits discrimination on the basis of disability. 

Airlines claimed parts of the rule are an overreach, particularly in how it defines discrimination. The petitioners argue an instance of a properly stored wheelchair being damaged by extreme turbulence or being unable to accommodate a wheelchair in cargo are not acts of discrimination.

“Progress has been made in four key areas aimed at improving the travel experience for passengers with mobility aids—reducing instances of wheelchair mishandling, advancing employee training and education programs, forming passenger accessibility advisory groups and supporting research for onboard accessibility solutions,” an A4A spokesperson told Fortune in a statement. The group said it was not challenging the entire rule.

“It’s important to note that while we have always been supportive of a wheelchair rule as reflected in our comments, certain provisions of the final rule go beyond the DOT’s statutory authority, violate the Administrative Procedure Act and represent regulatory overreach by the Biden Administration,” the statement continued.

Most of the airlines declined requests for comment, referring to A4A’s statement instead. JetBlue and the DOT did not respond to Fortune’s requests for comment.

Airlines’ history of mishandling wheelchairs

About 5.5 million Americans are wheelchair users, but airlines mishandled 11,527 wheelchairs and scooters in 2023, according to DOT data. The Biden-era rule imposed a steep fine of up to $124,000 for airlines that violated the guidelines.

“We’re really trying to make clear that just like a number of other passenger protections required by rule and by law, taking proper care of wheelchairs and the passengers to use them is fundamental and is required,” then-Transportation Secretary Pete Buttigieg told reporters when the rule was proposed last February. “And there are consequences for airlines that don’t do that.”

In October, the DOT penalized American Airlines $50 million after an investigation found the carrier between 2019 and 2023 had repeatedly mishandled wheelchairs or delayed returning them to passengers, as well as injured passengers as a result of “unsafe physical assistance.” A 2023 video cited by the DOT shows an airline worker sending a wheelchair down a ramp while unloading baggage, causing it to crash and flip over.

Samantha Jade Durán, a disability advocate who worked with Buttigieg in creating the rule, said many airlines are still not acting in the interest of their disabled customers. In 2017, Durán’s wheelchair was damaged during a flight after it was placed in a cargo hold.

“Airlines have disregarded our mobility aids, spoken about our disabilities like they’re a burden, and put profits over our basic safety,” Durán said on social media Thursday in response to the airlines’ lawsuit. “We deserve better.”