CDC has issued an order that requires face masks to be worn by all travelers while on public transportation (which includes all passengers and all personnel operating vehicles). People must wear masks that completely cover both the mouth and nose while awaiting, boarding, disembarking, or traveling on airplanes, ships, ferries, trains, subways, buses, taxis, and ride-shares as they are traveling into, within, or out of the United States and U.S. territories. Public transportation operators must use best efforts to ensure that any person on the vehicle wears a mask when boarding, disembarking, and for the duration of travel. Depending on the circumstances, public transportation operators must take the following actions:

Board only those wearing a mask.
Instruct people that wearing a mask on the vehicle is a requirement of federal law and that not complying with the requirement is a violation of federal law.

For the full article and for more information visit: https://www.cdc.gov/quarantine/masks/mask-travel-guidance.html