The Centers for Disease Control and Prevention has announced new guidance that fully vaccinated people can safely do most indoor and outdoor activities without wearing masks or social distancing.

But much of the transportation sector still operates on pandemic-era rules. Here's what is and isn't changed by the updated guidance.

What does the new guidance mean for mask requirements on public transit and air travel?

For now, nothing changes. Separate from its general guidance on mask-wearing, the CDC has a previously issued order requiring masks on public transportation, and those rules are unchanged.

"Right now, we still have the requirement to wear masks when you travel on buses, trains and other forms of public transportation, as well as airports and stations," CDC Director Rochelle Walensky told NPR on Thursday. The CDC will continue to update its guidance as the science emerges, she added.

The CDC requires that masks be worn by travelers on all planes, buses, trains and other forms of public transportation traveling into, within or out of the United States and in U.S. transportation hubs such as airports and stations.

The Transportation Security Administration sets rules for airports, commercial aircraft, bus companies and commuter bus and rail systems. The TSA announced two weeks ago that it was extending its mask requirement at airports, on planes and on public transit through Sept. 13.

A TSA spokesperson told NPR on Thursday that no changes to the rules are expected anytime soon.

In New York City, Mayor Bill de Blasio called the mask news "monumental" and said his administration is reviewing the CDC's guidance "because masks will still be important for schools, public transportation, health care and congregate settings and more." A spokesman for the city's transit agency, MTA, said masks continue to be required throughout its transportation network, both indoors and on outdoor platforms, until further notice.

The Chicago Transit Authority says it will continue to follow the TSA rules requiring masks.

What about testing or quarantine around travel?

For domestic travel, the CDC says that fully vaccinated travelers now do not need to get tested before or after travel, unless testing is required by local, state or territorial health authorities. They also do not need to quarantine.

For international travel, the CDC says fully vaccinated travelers arriving in the United States are still required to get tested within three days before their flight (or show documentation of recovery from COVID-19 in the past three months) and should still get tested three to five days after their trip. Other countries may continue to require testing or quarantine for arriving U.S. travelers.

The CDC says it is now reviewing its guidance for travelers, based on Thursday's updated guidance for vaccinated people.

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