New CDC Guidelines Require Proof of Negative Test on inbound international flights. The Centers for Disease Control and Prevention has ordered that all travelers flying to the U.S. from abroad will have to show proof of negative Covid-19 tests before boarding their flight starting Jan. 26. The CDC said preflight testing is necessary as Covid-19 cases continue to soar and more-contagious strains of the virus emerge around the world. President Biden signed an executive order on Jan. 21 affirming the new testing requirements and directing agencies to consider additional travel-safety measures. Who It Affects: The order ... (full story)