Photo taken on Aug. 22, 2021 shows a commercial plane approaching Ronald Reagan Washington National Airport in Arlington, Virginia, the United States. U.S. Secretary of Defense Lloyd Austin ordered U.S. airlines to provide 18 aircraft to support evacuation missions from Afghanistan, the Pentagon said on Sunday.(Xinhua/Liu Jie)

Photo taken on Aug. 22, 2021 shows a commercial plane approaching Ronald Reagan Washington National Airport in Arlington, Virginia, the United States. U.S. Secretary of Defense Lloyd Austin ordered U.S. airlines to provide 18 aircraft to support evacuation missions from Afghanistan, the Pentagon said on Sunday.(Xinhua/Liu Jie)

Photo taken on Aug. 22, 2021 shows a commercial plane approaching Ronald Reagan Washington National Airport in Arlington, Virginia, the United States. U.S. Secretary of Defense Lloyd Austin ordered U.S. airlines to provide 18 aircraft to support evacuation missions from Afghanistan, the Pentagon said on Sunday.(Xinhua/Liu Jie)

Photo taken on Aug. 22, 2021 shows a commercial plane approaching Ronald Reagan Washington National Airport in Arlington, Virginia, the United States. U.S. Secretary of Defense Lloyd Austin ordered U.S. airlines to provide 18 aircraft to support evacuation missions from Afghanistan, the Pentagon said on Sunday.(Xinhua/Liu Jie)