Even as fugged up as the country is right now, I was surprised to learn this after reading this thread.

Effective December 6, the  Centers for Disease Control and Prevention (CDC) will require all air passengers two years of age and over entering the United States (including U.S. citizens and Legal Permanent Residents) to present a negative COVID-19 test result a negative taken no more than 1 day before departure​, or proof of recovery from the virus within the last 90 days. Airlines must confirm the negative test result or proof of recent recovery for all passengers prior to boarding. ​Airlines must deny boarding of passengers who do not provide documentation of a negative test or recovery.


https://travel.state.gov/content/tr.../covid-19_testing_required_US_Entry.html