A decision by a federal judge in Florida to throw out a national mask mandate for public transportation across the U.S. created a confusing patchwork of rules for passengers as they navigate airports and transit systems.

The ruling gives airports, mass transit systems, airlines and ride-hailing services the option to keep mask rules or ditch them entirely, resulting in rules that vary by city and mode of transportation.

Passengers on a United Airlines flight from Houston to New York, for instance, could ditch masks at their departing airport and on the plane, but would have to put them back on once they get off their flight in New York.

The U.S. Centers for Disease Control and Prevention had recently extended the mandate until May 3 to allow more time to study the BA.2 omicron subvariant of the coronavirus now responsible for the vast majority of U.S. cases. But the court decision put the mandate on hold.