Travelers scrambled after President Donald Trump announced a travel suspension from Europe for the next 30 days to try to slow the spread of the coronavirus.

Adding to the uncertainty: The U.S. State Department and the Centers for Disease Control and Prevention issued global travel warnings Wednesday, calling on Americans to avoid nonessential travel to Europe.

Here’s what travelers need to know:

What’s included in the ban?

Trump said the administration would restrict “all travel” to the USA from continental Europe, which is reeling from the epidemic, for the next 30 days. The United Kingdom is exempted.

Who is covered by the ban?

The Department of Homeland Security said the order suspends the entry of most foreign nationals who have been in certain European countries at any point during the 14 days before their scheduled arrival to the USA.

These countries include Austria, Belgium, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Italy, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden and Switzerland.

How will this affect Americans traveling from Europe?

Homeland Security plans to issue a notice requiring U.S. passengers who have been traveling in parts of Europe to “travel through select airports where the U.S. Government has implemented enhanced screening procedures,” acting Secretary Chad Wolf said.

Vice President Mike Pence said in an interview with CNN on Thursday that Americans and documented residents returning to the USA from Europe will be funneled through 13 airports for screening. 

Pence did not name the airports, but an advisory on American Airlines’ website lists 11, the same airports where travelers coming from China have been screened. Airlines await a complete list from the government.

The listed airports:

  • Atlanta Hartsfield–Jackson Atlanta International Airport
  • Dallas Fort Worth International Airport
  • Detroit Metropolitan Airport
  • Newark Liberty International Airport
  • Honolulu’s Daniel K. Inouye International Airport
  • New York JFK
  • Los Angeles International Airport
  • Chicago O’Hare International Airport
  • Seattle-Tacoma International Airport
  • San Francisco International Airport
  • Washington-Dulles International Airport

American and other airlines said travelers who are not scheduled to fly through one of the airports will be rebooked on a flight that goes through one of them.

Once home, U.S. travelers will have to self-quarantine for 14 days, Pence said.

When does the ban take effect?

Midnight Friday.

How are airlines reacting?

Major U.S. airlines said they would implement the policies.

Delta cited “the safety and health of our customers and employees” in saying it “will continue to quickly make adjustments to service, as needed, in response to government travel directives.” A United spokeswoman, Leslie Scott, said that as details of the plan become known, “we will comply with the administration’s announcement.”

One airline noted that the plan remains fuzzy. In a tweet, Finland national carrier Finnair said it will let passengers know details as soon as it receives them, and it apologized “about the uncertainty this is causing to our customers.”

What about trips already booked?

Delta issued a travel waiver late Wednesday covering flights between the USA and Europe, raising the possibility that other carriers would follow suit. Delta said it will waive ticket change fees for passengers traveling to, from or through Europe and the U.K. through May 31. The waiver applies to travelers who purchased tickets before March 11.

Is there another way to catch a flight from Europe to the USA?

The U.K. exemption opens a lot of possibilities for connecting flights to the continent. London Heathrow is one of the world’s busiest connecting hubs.

How sudden is this?

The travel suspension announcement is sweeping, but Delta, American and United had already canceled flights to northern Italy because of earlier restrictions there.

Plenty of travelers canceled spring flights to Europe out of anxiety, so Europe flights were hurting before Trumps’s ban. United said Tuesday that bookings to Europe were down 50%.

It doesn’t matter that Trump mentioned only flights from Europe to the USA, not flights in both directions, said Brett Snyder, a former airline employee who runs the Cranky Concierge travel service. Travelers will cancel flights en masse during the busy spring break travel season.

“If they can’t come home, they’re not going to Europe,” he said.

Why is this happening?

Coronavirus is spreading around the world. Italy has been hit hard, with more than 12,000 confirmed infections and more than 800 deaths, according to Johns Hopkins University data. France, Spain and Germany each have about 2,000 confirmed cases.

The restrictions will “deny entry to foreign nationals who have been in affected areas and will keep Americans safe and save American lives,” Wolf said.

Other travel restrictions?

The administration has already restricted travel from China and Iran.

What will the travel ban do to the airline industry?

It is likely to make a bad situation worse in the name of public safety.

The travel and tourism industry has taken hit after hit since the coronavirus outbreak began in January. Though it’s still early for concrete data, economists and industry executives fear 9/11- or recession-like repercussions.

U.S. airlines began suspending and cutting international flights in late January and have repeatedly added reductions to destinations. The cuts are poised to spread to flights within the USA as travelers worry about the risks of flying anywhere, not just abroad.

United Airlines said last week it will cut its domestic seat capacity by 10% in April and May, and JetBlue said it is making 5% cuts. Tuesday, American said it will reduce international seat capacity by 10% this summer, including a 55% reduction in flights across the Pacific. Flights within the USA will be reduced by 7.5% for April.

At the White House on Monday, Trump said he wanted to work with the airline and cruise industries to help them weather the coronavirus fallout.

“We’ll be helping them through this patch,” Trump said at a meeting with health insurance executives.

What do the CDC and State Department say?

After Trump’s announcement late Wednesday, the U.S. State Department issued a global advisory urging Americans to “reconsider” all travel abroad. The CDC warned Americans to avoid nonessential travel to 29 European countries and principalities.

None of the guidance they issued late Wednesday explicitly tells U.S. citizens to not travel to Europe or abroad. In early February, the State Department advised Americans to not travel to China. The CDC urges Americans to avoid nonessential travel to China and South Korea.