A woman walks past posters explaining mask requirements at Grand Central Terminal train station in New York City on Wednesday. Rules requiring masks on transit are unchanged by the Centers for Disease Control and Prevention's updated mask guidance for fully vaccinated people. Angela Weiss/AFP via Getty Images hide caption
Prime Minister Jacinda Ardern announced that quarantine-free travel between New Zealand and Australia will start on April 19. Hagen Hopkins/Getty Images hide caption
The Centers for Disease Control and Prevention updated its domestic travel guidance for fully vaccinated people on Friday, lifting certain requirements while continuing to advise mitigation measures like mask-wearing and hand-washing. Angus Mordant/Bloomberg via Getty Images hide caption
For lighter moments during the coronavirus pandemic, passersby had an opportunity to vote for their stay at home spring break moments on the retaining wall of a home in St. Paul, Minn. Jim Mone/AP hide caption
A British Airways plane comes in to land behind a tail fin at Heathrow Airport in London. On Friday, the head of the group that owns BA called for instituting an electronic health pass for passengers as the company announced steep losses due to COVID-19. Kirsty Wigglesworth/AP hide caption
A jetliner arrives at London's Heathrow Airport earlier this year. On Wednesday, the U.K.'s highest court reversed a ban on the airport's controversial plans for a third runway. Adrian Dennis/AFP via Getty Images hide caption
There's increasing emphasis on wearing masks while flying. How much protection do they offer against COVID-19? James D. Morgan/Getty Images hide caption
Dozens of Delta jets have been parked on the tarmac of the Birmingham-Shuttlesworth International Airport since last spring. The airline reported $5.4 billion in third quarter losses on Tuesday. Russell Lewis/NPR hide caption
An American Airlines plane lands at the Fort Lauderdale-Hollywood International Airport on July 16, 2020. Air traffic has rebounded a bit but it's way below pre-coronavirus levels. Joe Raedle/Getty Images hide caption
A flight attendant adjusts protective glasses. There has been little documentation about COVID-19 transmission on planes. Valentyn Ogirenko/Reuters hide caption
Many airlines now require passengers to wear masks to reduce the risk of COVID-19 spread — and are putting scofflaws on a no-fly list. Nicolas Economou/ NurPhoto via Getty Images hide caption
A man wearing a mask prepares to board a Southwest Airlines flight at Kansas City International airport in Kansas City, Mo. Southwest and American Airlines are tightening their mask requirements at the end of July by doing away with exemptions for travelers over the age of 2. Charlie Riedel/AP hide caption
United Airlines planes at Newark Liberty International Airport in Newark, N.J. Company executives call the COVID-19 pandemic the worst crisis in the airline's history. Seth Wenig/AP hide caption
Passengers are tested for COVID-19 at Beirut International Airport on July 1. Anwar Amro/AFP via Getty Images hide caption