The Centers for Disease Control and Prevention said the Biden administration is extending a mask mandate for 15 days.
The mandate was extended for one month in March. The Biden administration made masks mandatory in early 2021.
The CDC said it is watching the spread of omicron.
Since early April, there have been increases in the 7-day moving average of cases in the U.S., in order to assess the potential impact the rise of cases has on severe disease, including hospitalizations and deaths, and health care system capacity, the CDC.
The mandate will last through May 3.
Airlines have repeatedly asked the administration to drop that requirement and other Covid restrictions, such as predeparture testing for all international arrivals, including citizens.
As the administration weighs the risks of Covid spread, the extensions to the mask mandate have become shorter. A decline in cases from a peak this winter helped fuel a surge in travel demand that is helping airlines cover much of their soaring fuel bills.