FILE - In this June 25, 2020, file photo, rows of United Airlines check-in counters at O'Hare International Airport in Chicago are unoccupied amid the coronavirus pandemic. On Sunday, Aug. 30, 2020, United Airlines says it will be dropping an unpopular $200 fee for most people who change a ticket for travel within the United States. (AP Photo/Teresa Crawford, File)

United Airlines is adding summer flights to Iceland, Croatia and Greece as they prepare to ease entry requirements for U.S. citizens. United is adding a Chicago to Reykjavik flight from July 1st through October 3rd after Iceland announced it would allow tourists who can show proof of being vaccinated. The company will also add service from Newark, New Jersey, to Dubrovnik, Croatia, and a Washington-Dulles to Athens flight after Greece said last month it would open its borders in mid-May.