Children under the age of 11 are exempt from presenting a COVID-19 test. They must also present a sworn statement that they do not show symptoms and are not aware of having been in contact with a confirmed case of COVID-19 in the fourteen days preceding the flight. Travelers who test positive for COVID-19 cannot fly.
Children under the age of 2 are exempt from presenting a COVID-19 test.
Travelers with proof of recovery from the virus within the last 90 days prior to boarding. Proof of a recent positive viral test and a letter from your healthcare provider or a public health official stating that you were cleared to travel.
More info at the CDC site
Travelers who did not get tested, are advised to stay home and self-quarantine for 10 days after travel.