Dulles International Airport last month. The CDC will require all air passengers entering the U.S. to provide a negative COVID-19 test before boarding their flight.

Passengers walk through a crowded terminal at Dulles International airport in Dulles, Virginia on December 27, 2020 amid the Coronavirus pandemic. – Top US government scientist Anthony Fauci warned today the worst of the pandemic may be yet to come, driving the country to a “critical point” as holiday travel spreads the coronavirus. (Photo by ANDREW CABALLERO-REYNOLDS / AFP) (Photo by ANDREW CABALLERO-REYNOLDS/AFP via Getty Images)