Children under 2 years of age and children who cannot wear a mask due to a disability are excluded from the regulation, which is due to come into force on Monday at 11:59 p.m.
The CDC’s new rule goes beyond an ordinance signed by President Joe Biden last week that requires face masks to be worn on federal properties and on interstate travel.
The CDC said that while it “reserves the right” to enforce the order through criminal penalties, it will rely on a passenger honor system.
The airlines, which prior to Biden’s order and the new CDC rule, had largely enforced self-imposed masking regulations, previously requested the Federal Aviation Administration to issue a federal masking mandate. However, the agency declined, stating that it was not a public health agency.
On Saturday morning, the U.S. topped 25,000,000 cases and 436,000 deaths amid the coronavirus pandemic.