Despite U.S. travelers going maskless for over a month on planes and public transportation, the Biden administration has formally filed an appeal to restore a mask mandate tor such modes of transportation.

In mid-April, a federal judge struck down the national mask mandate for public transportation and air travel. After nearly a day when the Biden administration appeared to concede the defeat, it vowed to appeal the matter in court.

That appeal is now filed in the United States District Court for the Middle District of Florida. It pits the Health Freedom Defense Fund vs. the Biden administration.

“To prevent the spread of COVID-19, the Centers for Disease Control and Prevention (CDC) issued an order that generally requires people to wear masks when traveling on public transportation and at transportation hubs,” the Biden administration argued. “The district court vacated the CDC order nationwide, ruling that the order exceeds the CDC’s statutory authority, that it is arbitrary and capricious, and that the CDC did not have good cause to make the order effective without delay. Another judge in the same district has since reached the opposite conclusion and upheld the transportation mask order.”

“Given the importance of the issues presented, the government respectfully requests oral argument,” the administration argued.

The Justice Department in April did not ask the court to stay the decision, meaning passengers would be able to continue traveling maskless while the decision is litigated.