https://www.cdc.gov/coronavirus/2019-ncov/travelers/international-travel-during-covid19.html#:~:text=Before%20boarding%20a%20flight%20todo%20not%20need%20to%20test.
Non-U.S. Citizen, Non-U.S. Immigrants
Proof of Vaccination
REQUIRED
Air Travel: All non-U.S. citizen, non-U.S. immigrants traveling to the United States by air are required to show proof of being fully vaccinated against COVID-19. Only limited exceptions apply. Learn more about this requirement and accepted vaccines.
If you are not fully vaccinated and allowed to travel to the United States by air through an exception, you will be required to sign an attestation (legal statement) before you board your flight to the United States stating you meet the exception. Depending on the type of exception, you may also have to state you have arranged to take certain protective measures.
For more information see Requirement for Proof of COVID-19 Vaccination for Air Passengers.