A traveler wearing a face mask is seen at Ronald Reagan Washington National Airport in Arlington, Virginia, the United States, Feb. 2, 2021. Begining Tuesday, Americans are required to wear face masks while traveling on domestic public transport as part of a national strategy to curb the spread of COVID-19. The mask-wearing rule which will go into effect at 11:59 p.m. Monday (0459 GMT Tuesday) makes refusal to wear a mask a violation of federal law, enforced by the Transportation Security Administration and other federal, state and local authorities. (Photo by Ting Shen/Xinhua)

A traveler wearing a face mask is seen at Ronald Reagan Washington National Airport in Arlington, Virginia, the United States, Feb. 2, 2021. Begining Tuesday, Americans are required to wear face masks while traveling on domestic public transport as part of a national strategy to curb the spread of COVID-19. The mask-wearing rule which will go into effect at 11:59 p.m. Monday (0459 GMT Tuesday) makes refusal to wear a mask a violation of federal law, enforced by the Transportation Security Administration and other federal, state and local authorities. (Photo by Ting Shen/Xinhua)

Travelers wearing face masks are seen at Ronald Reagan Washington National Airport in Arlington, Virginia, the United States, Feb. 2, 2021. Begining Tuesday, Americans are required to wear face masks while traveling on domestic public transport as part of a national strategy to curb the spread of COVID-19. The mask-wearing rule which will go into effect at 11:59 p.m. Monday (0459 GMT Tuesday) makes refusal to wear a mask a violation of federal law, enforced by the Transportation Security Administration and other federal, state and local authorities. (Photo by Ting Shen/Xinhua)

Travelers wearing face masks are seen at Ronald Reagan Washington National Airport in Arlington, Virginia, the United States, Feb. 2, 2021. Begining Tuesday, Americans are required to wear face masks while traveling on domestic public transport as part of a national strategy to curb the spread of COVID-19. The mask-wearing rule which will go into effect at 11:59 p.m. Monday (0459 GMT Tuesday) makes refusal to wear a mask a violation of federal law, enforced by the Transportation Security Administration and other federal, state and local authorities. (Photo by Ting Shen/Xinhua)

A traveler wearing a face mask is seen at Ronald Reagan Washington National Airport in Arlington, Virginia, the United States, Feb. 2, 2021. Begining Tuesday, Americans are required to wear face masks while traveling on domestic public transport as part of a national strategy to curb the spread of COVID-19. The mask-wearing rule which will go into effect at 11:59 p.m. Monday (0459 GMT Tuesday) makes refusal to wear a mask a violation of federal law, enforced by the Transportation Security Administration and other federal, state and local authorities. (Photo by Ting Shen/Xinhua)

Travelers wearing face masks are seen at Ronald Reagan Washington National Airport in Arlington, Virginia, the United States, Feb. 2, 2021. Begining Tuesday, Americans are required to wear face masks while traveling on domestic public transport as part of a national strategy to curb the spread of COVID-19. The mask-wearing rule which will go into effect at 11:59 p.m. Monday (0459 GMT Tuesday) makes refusal to wear a mask a violation of federal law, enforced by the Transportation Security Administration and other federal, state and local authorities. (Photo by Ting Shen/Xinhua)

Travelers wearing face masks are seen at Ronald Reagan Washington National Airport in Arlington, Virginia, the United States, Feb. 2, 2021. Begining Tuesday, Americans are required to wear face masks while traveling on domestic public transport as part of a national strategy to curb the spread of COVID-19. The mask-wearing rule which will go into effect at 11:59 p.m. Monday (0459 GMT Tuesday) makes refusal to wear a mask a violation of federal law, enforced by the Transportation Security Administration and other federal, state and local authorities. (Photo by Ting Shen/Xinhua)

Travelers wearing face masks are seen at Ronald Reagan Washington National Airport in Arlington, Virginia, the United States, Feb. 2, 2021. Begining Tuesday, Americans are required to wear face masks while traveling on domestic public transport as part of a national strategy to curb the spread of COVID-19. The mask-wearing rule which will go into effect at 11:59 p.m. Monday (0459 GMT Tuesday) makes refusal to wear a mask a violation of federal law, enforced by the Transportation Security Administration and other federal, state and local authorities. (Photo by Ting Shen/Xinhua)

Travelers wearing face masks are seen at Ronald Reagan Washington National Airport in Arlington, Virginia, the United States, Feb. 2, 2021. Begining Tuesday, Americans are required to wear face masks while traveling on domestic public transport as part of a national strategy to curb the spread of COVID-19. The mask-wearing rule which will go into effect at 11:59 p.m. Monday (0459 GMT Tuesday) makes refusal to wear a mask a violation of federal law, enforced by the Transportation Security Administration and other federal, state and local authorities. (Photo by Ting Shen/Xinhua)

Travelers wearing face masks are seen at Ronald Reagan Washington National Airport in Arlington, Virginia, the United States, Feb. 2, 2021. Begining Tuesday, Americans are required to wear face masks while traveling on domestic public transport as part of a national strategy to curb the spread of COVID-19. The mask-wearing rule which will go into effect at 11:59 p.m. Monday (0459 GMT Tuesday) makes refusal to wear a mask a violation of federal law, enforced by the Transportation Security Administration and other federal, state and local authorities. (Photo by Ting Shen/Xinhua)

A traveler wearing a face mask is seen at Ronald Reagan Washington National Airport in Arlington, Virginia, the United States, Feb. 2, 2021. Begining Tuesday, Americans are required to wear face masks while traveling on domestic public transport as part of a national strategy to curb the spread of COVID-19. The mask-wearing rule which will go into effect at 11:59 p.m. Monday (0459 GMT Tuesday) makes refusal to wear a mask a violation of federal law, enforced by the Transportation Security Administration and other federal, state and local authorities. (Photo by Ting Shen/Xinhua)