The Centers for Disease Control and Prevention said it would extend the federal transportation mask requirement for two weeks on Wednesday, five days before it was set to end. The agency said that the mandate was extended through May 3.

The C.D.C. said that the Omicron subvariant of the coronaviruses known as BA.2 makes up more than 85% of new U.S. virus cases.

There have been increases in the 7-day moving average of cases since early April.

Dr. Rochelle Walensky, the director of the C.D.C., told NBC that they were going to make a decision.

We will make a decision collectively based on that, he said while simultaneously calling it a C.D.C. decision.

New U.S. cases have begun to pick up again. According to a New York Times database, the nation reported more than 31,000 new cases a day on average, 8 percent more than two weeks before, though the case counts have not reached the peak seen in the winter Omicron surge.

The true spread of the virus may be undercounted since access to at- home tests has increased and the results are not officially reported.

The possibility of an extension was applauded by some travelers and commuters, who said the requirement made them feel safer in crowded planes, airports and buses, as new versions of the requirement spread, and disappointment from others, who felt that it was nonsensical to require masks in the sky and in airports. Public health experts say masks help slow the spread of the virus.

Ari Fleischer, a media consultant who served as a White House spokesman for President George W. Bush, said on Wednesday that this is absurd.

One of the organizers of the March for Science, Dr. Lucky Tran, took a different stance on the same platform.

The C.D.C. is extending the mask mandate for two weeks. Millions of people rely on public transportation to get to work.

In recent months, airlines and the hotel industry have been lobbying the White House to overturn the mask rule and the requirement to test before returning to the United States from abroad. In one of the most recent letters, dated April 8, Airlines for America, an industry group representing eight airlines; the U.S. Travel Association, a trade group that caters to business and leisure travelers.

While the public health benefits of these policies have diminished, the economic costs associated with maintaining these measures are significant.

Airlines for America sent another letter to the C.D.C. director on Wednesday, asking for a detailed explanation of why masks are necessary on planes.

Nicholas E. Calio, the president of the group, wrote that if the federal mask mandate is extended, the administration should publish the data and science used to reach that.

Many passengers have been physically and mentally abusive towards flight attendants who have told them to cover their nose and mouth. The two groups that have to deal with implementing the rule were not represented by major unions.

The president of the union that represents Transportation Security Administration employees said on Tuesday that they have to comply with whatever the agency puts in place. He believes that masks protect his employees, their families and the flying public.

The mask rule could be extended by the C.D.C.