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
An empty terminal at Chicago's O'Hare International Airport. The normally bustling check-in at the United Airlines terminal was eerily quiet on April 24. David Schaper/NPR hide caption
The Boeing headquarters is seen amid the coronavirus pandemic on April 29, in Arlington, Va. Boeing announced sweeping cost-cutting measures Wednesday after reporting a first-quarter loss of $641 million following the hit to the airline business from the coronavirus pandemic. Olivier Douliery/AFP via Getty Images hide caption
With the coronavirus outbreak taking hold in the U.S., thousands of flights have been canceled — but on Sunday, there were still 2,800 planes in the air, according to aviation site Flightradar.com Courtesy of Flightradar24.com hide caption
Travelers have lots of new coronavirus-related questions about booking — and canceling — flights. Bim/Getty Images hide caption
An airplane arrives at London's Heathrow Airport on Thursday — the same day a court blocked plans for a third runway at the airport, citing the government's climate change commitments. Chris J. Ratcliffe/Getty Images hide caption
Where should you sit on a plane to reduce the risk of exposure to germs spread by infectious passengers? skaman306/Getty Images hide caption
Commercial air travel currently accounts for just about 2.5% of global carbon emissions, but those emissions are rising fast. Elaine Thompson/AP hide caption
Australian airline Qantas is exploring new nonstop flights that would be the world's longest — but 19-plus hours on a plane can be taxing for those on board. Qantas hide caption
Passengers wait Friday at London's Gatwick Airport, where drone sightings repeatedly caused flights to be delayed and suspended at the height of holiday travel season. Jack Taylor/Getty Images hide caption
Three major U.S. airlines have announced new restrictions on "smart luggage" because of the fire hazard posed by lithium-ion batteries in cargo holds. The airlines say any such batteries need to be removable. Rob Carr/Getty Images hide caption
The U.S. announced Wednesday that it had lifted the laptop ban that originally affected nine airlines, including Qatar Airways. Don Emmert/AFP/Getty Images hide caption