Cue the federal mask cops. Americans are now required to wear masks in planes, trains, buses, subways, taxis, car services, boats, and transportation hubs, per a new order from the Centers for Disease Control and Prevention (CDC) that took effect today. Masks must be of a style approved by the federal government and must fit properly. Failure to comply will result in being prohibited from traveling, booted from the transit in question, and potential criminal penalties.