From CNN:

THE CDC ANNOUNCED AN ORDER LATE FRIDAY THAT WILL REQUIRE PEOPLE TO WEAR A FACE MASK WHILE USING ANY FORM OF PUBLIC TRANSPORTATION, INCLUDING BUSES, TRAINS, TAXIS, AIRPLANES, BOATS, SUBWAYS OR RIDE-SHARE VEHICLES WHILE TRAVELING INTO, WITHIN AND OUT OF THE US.

THE ORDER GOES INTO EFFECT AT 11:59 P.M. MONDAY.

MASKS MUST BE WORN WHILE WAITING, BOARDING, TRAVELING AND DISEMBARKING, IT SAID. THE COVERINGS NEED TO BE AT LEAST TWO OR MORE LAYERS OF BREATHABLE FABRIC SECURED TO THE HEAD WITH TIES, EAR LOOPS OR ELASTIC BANDS — AND SCARVES AND BANDANAS DO NOT COUNT, THE ORDER SAYS.

THE CDC SAID IT RESERVES THE RIGHT TO ENFORCE THE ORDER THROUGH CRIMINAL PENALTIES, BUT IT "STRONGLY ENCOURAGES AND ANTICIPATES WIDESPREAD VOLUNTARY COMPLIANCE" AND EXPECTS SUPPORT FROM OTHER FEDERAL AGENCIES TO IMPLEMENT THE ORDER.

On top of now having to wear TWO masks, the CDC has also deemed Bandannas and neck gaiters unacceptable and are not on the list of Government approved masks!