It’s not often rival carriers join forces on anything in the competitive aviation industry. But this week, three of Europe’s biggest airlines teamed up to sue the U.K. government over plans to force visitors to self-isolate for 14 days.

On Friday, British Airways, EasyJet Plc and Ryanair Holdings Plc said they asked for London judges to hear a case against the quarantine.

The airlines say the rules, which began Monday, “will have a devastating effect on British tourism and the wider economy and destroy thousands of jobs.” They want the government to roll its plan back to rules in force since March 10, which required only travelers from “high risk” countries to self-isolate. The government is yet to respond to the airlines’ challenge announcement.

Now that the case has been filed, a court proceeding known as a judicial review can take place within a week or two under an expedited timeline. The court hearings themselves usually last just a few days.

The sides will make arguments over whether the decision-making process was fair and rational. Prime Minister Boris Johnson’s government will likely argue that the policy decision was complex, and base its justification on recommendations of doctors and scientists, said Sophie Kemp, a partner at Kingsley Napley, who has represented both government bodies and claimants in judicial reviews.

Matthew Smith, a partner at BDB Pitmans and former government lawyer, said the government’s reliance on the advice of scientists opens up a role for the courts.

The government’s “default cry that ‘we’re being led by the science’ puts the airlines in a stronger position,” Smith said. “It won’t be easy to say that the courts have no role here.”

British Airways will likely focus on the government’s decision to end its program in March for repatriation flights that was based on individual risk assessment, Kemp said. The new plan is much more of a blanket approach to quarantine, she said.

Global carriers have been some of the worst hit businesses from the economic fallout of Covid-19 and are desperate to salvage the summer season when tens of millions of people generally take their vacation.

The International Air Transport Association on Tuesday predicted carriers will lose a combined $84 billion this year and almost $16 billion in 2021, its first estimate of the hit to earnings since the coronavirus crisis began. That compares with $31 billion during the 2008-2009 recession.

The quarantine would torpedo BA’s plans to resume about 40% of its scheduled flights in July and force it to continue burning 20 million pounds ($25 million) a day, the carrier said. EasyJet is planning to resume some scheduled flights June 15, while Ryanair plans to restart flying July 1.

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Judicial reviews allow members of the public and corporations to hold the government accountable for policy decisions. The process is designed to weigh the lawfulness of how a government decision was reached, rather than on whether the decision is right or wrong. Public bodies that lose judicial review cases can make the same decision again as long as they do so using correct procedures.

Johnson, who was stung by a series of court challenges led by businesswoman Gina Miller over his plan to leave the European Union, has been critical of the courts’ role in political decisions. Earlier this year, he complained that judicial reviews shouldn’t be used “to conduct politics by another means or to create needless delays.”

This new suit opens the door once again to judicial scrutiny at an incredibly sensitive time for the government.

“The Miller case has seen the courts flex their muscles and assert their rights to ensure that political decisions are made within the rule of law,” Smith said. “There is a place for judges to review government decision-making in this case.”

While the airlines wait for the case to reach court, they could seek an injunction to stop the policy in the meantime. That would be unlikely however, as it’s a more difficult legal threshold to reach, Kemp said.

“This is likely going to be a complex challenge because we’re in unprecedented circumstances and the government is having to make policy decisions in difficult times,” she said.