The Biden administration will no longer enforce a US mask mandate on public transportation, after a federal judge in Florida on Monday ruled that the 14-month-old directive was unlawful, overturning a key White House effort to reduce the spread of Covid-19.

Soon after the announcement, United Airlines (UAL.O) and Alaska Airlines (ALK.N) relaxed the restrictions effective immediately on all domestic flights.

The ruling by US District Judge Kathryn Kimball Mizelle, an appointee of President Donald Trump, came in a lawsuit filed last year in Tampa, Florida, by a group called the Health Freedom Defence Fund.

Judge Mizelle said the US Centres for Disease Control and Prevention (CDC) had exceeded its authority with the mandate, had not sought public comment and did not adequately explain its decisions.

A US administration official said while the agencies were assessing potential next steps, the court’s decision meant CDC’s public transportation masking order was no longer in effect. The administration could still opt to appeal the order or seek an emergency delay in the order’s enforcement.

“Therefore, TSA will not enforce its Security Directives and Emergency Amendment requiring mask use on public transportation and transportation hubs at this time,” the official said in a statement.

“CDC recommends that people continue to wear masks in indoor public transportation settings.”

The ruling comes as Covid-19 infections rise again in the United States, with 36,251 new infections reported on average each day, and 460 daily deaths, based on a seven-day average – the highest number of reported total Covid-19 deaths in the world.

The White House called the ruling “disappointing.”

Last week, U.S. health officials extended by 15 days the mandate requiring travellers to wear masks on aeroplanes, trains, and in taxis, ride-share vehicles or transit hubs, saying they needed time to assess the impact of a recent rise in Covid-19 cases.

Industry groups and Republican lawmakers had wanted the administration to end the 14-month-old mask mandate last week.

United Airlines said on Monday masks are no longer required on domestic flights and select international ones, or at US airports. Alaska Airlines said face masks are now optional on its planes.

The TSA and Federal Aviation Administration (FAA) declined to comment. The CDC declined to comment.

The CDC first issued a public health order requiring masks for interstate transportation in February 2021. The TSA issued a security directive to enforce the CDC order.

Since January 2021, there have been a record 7,060 unruly passenger incidents reported, 70% involving masking rules, according to the FAA.

After the ruling, Sara Nelson, president of the Association of Flight Attendants, urged “calm and consistency in the airports and on planes. The last thing we need for workers on the frontlines or passengers travelling today is confusion and chaos.”

Airlines for America, which represents major U.S. passenger airlines, said after the announcement they are “strong advocates for eliminating pandemic-era policies and are encouraged by the lifting of the federal transportation mask mandate.”

The US Senate voted 57-40 last month to overturn the public health order requiring masks on aeroplanes and other forms of public transportation, drawing a veto threat from President Joe Biden.