Air travel

FILE - In this Saturday, Dec. 26, 2020 file photo, people walk with their luggage through a deserted check-in hall at the airport in Munich, Germany as Germany continues its second lockdown to avoid the further outspread of the coronavirus. On Tuesday, Jan. 12, 2021, the U.S. government said it will require airline passengers entering the country to show proof of a negative COVID-19 test before boarding their flights. It will take effect Jan. 26. (AP Photo/Matthias Schrader)

A plough clears snow in downtown Madrid, Spain, Sunday, Jan. 10, 2021. A large part of central Spain including the capital of Madrid slowly cleared snow after the country's worst snowstorm in recent memory. (AP Photo/Manu Fernandez)

McCarran International Airport/Twitter

Medical workers wearing protective gear prepare for a coronavirus test at a coronavirus testing site in Seoul, South Korea, Sunday, Dec. 27, 2020. (Park Min-suk/Newsis via AP)

FILE - In this Dec. 20, 2020, file photo, passengers queue for check-in at Gatwick Airport in West Sussex, England, south of London. The United States will require airline passengers from Britain to get a negative COVID-19 test before their flight, the Centers for Disease Control and Prevention announced late Thursday, Dec. 24. The U.S. is the latest country to announce new travel restrictions because of a new variant of the coronavirus that is spreading in Britain. (Gareth Fuller/PA via AP)

FILE - In this Sunday, Nov. 29, 2020 file photo, a traveler wears a mask as she walks through Terminal 3 at O'Hare International Airport in Chicago. The Transportation Security Administration said nearly 1.2 million people went through U.S. airports on Sunday, the highest number since the coronavirus pandemic gripped the country back in March, despite the pleadings of public health experts for people to stay home over Thanksgiving. (AP Photo/Nam Y. Huh, File)

Empty seats at Levi's Stadium are shown during the first half of an NFL football game between the San Francisco 49ers and the Green Bay Packers in Santa Clara, Calif., Thursday, Nov. 5, 2020. (AP Photo/Jeff Chiu)

This Nov. 13, 2020 photo provided by Lost Dog and Cat Rescue Foundation shows a handler holding a rescue dog from Georgia in Falls Church, Va. Kim Williams, who volunteers for the Lost Dog and Cat Rescue Foundation says he has tapped into a puppy pipeline to bring some of Georgia’s homeless pet population to the mid-Atlantic region, where demand is outrunning the number of dogs available for adoption.(Kim Williams/The Lost Dog and Cat Rescue Foundation via AP)

Qantas Chief Executive Officer Alan Joyce gestures during a results announcement in Sydney, Thursday, Aug. 20, 2020. Qantas Airways announced that the pandemic cost it 4 billion Australian dollars ($2.9 billion) in revenue in the last fiscal year and warned that international travel won't resume before mid 2021. (Dean Lewins/AAP Image via AP)

Travelers leave the AirTrain at JKF International Airport Friday, Nov. 20, 2020, in New York. Rising U.S. coronavirus cases, a new round of state lockdowns and public health guidance discouraging trips are dampening enthusiasm for what is usually the biggest travel period of the year. (AP Photo/Frank Franklin II)