On 3 February 2021, the Centers for Disease Control and Prevention (CDC) published a regulation requiring wearing a mask in airports, train stations, and other transportation hubs as well as on airplanes, buses, trains, and most other public conveyances in the United States. The Biden Administration extended the mandate until 3 May 2022.
However, by order of 18 April 2022, the District Court for the Middle District of Florida vacated the mandate and remanded it to the CDC. According to the Court, the mandate exceeded the CDC's statutory authority and violated the procedures required for agency rulemaking under the Administrative Procedure Act. More precisely, the Court emphasized that the relevant statute gave the CDC power to directly regulate individuals only if they are traveling into the United States from abroad or are "reasonably believed to be infected with a communicable disease in a qualifying stage”, while the mask mandate applied to all travelers without any such distinctions. In a vein similar to that of the Supreme Court in the case of the OSHA vaccine mandate, the federal court of Florida held that the CDC’s statute “has no "unmistakably clear" language indicating that Congress intended for the CDC to invade the traditionally State-operated arena of population-wide, preventative public-health regulations”.
Because of the ruling, the mandate is no longer in effect and would not be enforced by the Transportation Security Administration (TSA). Transport operators are thus free to make their own decisions about mask requirements. In the meantime, while strongly recommending that people continue to wear masks in indoor public transportation settings, the CDC urged the Department of Justice to file an appeal against the decision, deeming that the mandate is still needed to protect public health. On 20 April 2022, the Biden Administration complied and filed a notice of appeal.