Travelers with face masks wait for public transportation services at the International Airport in Los Angeles, California, the United States, on Feb 1, 2021. [Photo/Xinhua]
Travelers wearing face masks are seen at Ronald Reagan Washington National Airport in Arlington, Virginia, the United States, Feb 2, 2021. [Photo/Xinhua]
A traveler wearing a face mask is seen at Ronald Reagan Washington National Airport in Arlington, Virginia, the United States, Feb 2, 2021. [Photo/Xinhua]
