All air passengers arriving at the United States from a foreign country will be required to be tested no more than 3 days before their flight departs, and to provide proof of the negative result to the airline before boarding the flight. This, per an Order issued this week by the Centers for Disease Control that will come into effect on January 26, 2021.
https://app.activetrail.com/S/eiwi3xdawew.htm
