U.S. requires proof of negative COVID-19 test result, recovery for all airline passengers

The United States (U.S.) Centers for Disease Control and Prevention (CDC) has issued an order for proof of a negative COVID-19 test or documentation of having recovered from COVID-19 for all air passengers arriving from a foreign country to the U.S.
The order issued on January 12, 2021 is inclusive of  U.S. citizens and non-U.S. citizens.
It will become effective on January 26, 2021.
A copy of the order can be seen on https://www.cdc.gov/quarantine/pdf/global-airline-testing-order_2021-01-2_R3-signed-encrypted-p.pdf