If a U.S. government shutdown goes on long enough, it could throw a wrench in travel plans, potentially leading to longer airport wait times, flight delays and even cancellations.
The shutdown began Wednesday after President Donald Trump and Congress failed to reach a deal to continue funding government services and operations. That means a vast majority of employees who keep U.S. airports and air travel running are working without pay until the government reopens.
"The longer a shutdown drags on, the more likely we are to see longer TSA lines, flight delays and cancellations, national parks in disrepair and unnecessary delays in modernizing travel infrastructure," Geoff Freeman, president and CEO of the U.S. Travel Association, warned in a statement.
Here's what to know about the shutdown and its potential impacts on your travel plans:
Travelers can still fly despite the lapse in funding, but during a prolonged shutdown, travelers should plan ahead for potentially longer lines at airport security and flight interruptions.
Control towers and airport security areas will still be staffed, with about 13,200 air traffic controllers and more than 61,000 Transportation Security Administration employees expected to remain on the job.
But if the shutdown persists, it could put a significant strain on the national aviation system. That's what happened in 2018 and 2019, when Trump led the country into its longest shutdown ever for 35 days during his first term.
About three weeks into that shutdown, some unpaid security screeners started calling in sick, and air traffic controllers sued the government in a bid to get their paychecks. Miami International Airport had to temporarily close one of its terminals because TSA officers were calling in sick at twice the airport's usual rate.
The latest shutdown is unfolding at a time when the Federal Aviation Administration is already facing a shortage of about 3,000 air traffic controllers.
Ports of entry into the country are expected to stay open for international travelers, according to the Department of Homeland Security's contingency plan.
The department estimated that about 63,000 workers at Customs and Border Protection would still report to work. They include employees who are responsible for protecting the country's borders and monitoring traffic coming into the U.S. at official border crossings, like airports and land crossings from Canada and Mexico.
The U.S. Citizenship and Immigration Services, the agency responsible for overseeing the naturalization process, is primarily funded by application fees, meaning a lapse in funding at the federal government has minimal impacts on most passport and visa processing.
Agency spokesperson Matthew Tragesser said in a statement, however, that the shutdown does temporarily shutter the agency's E-Verify program, a free online system that employers can use to confirm their new employees are authorized to work in the U.S.
Smithsonian museums, research centers and the National Zoo were scheduled to stay open to the public through at least Oct. 6. Further updates will be posted on the Smithsonian website.
The Smithsonian is the world's largest museum complex, with 17 museums and its zoo located in the Washington, D.C. area, as well as two museums in New York City.
National Parks will remain mostly open during the shutdown.
The National Park Service's contingency plan says park roads, lookouts, trails and open-air memorials will "generally remain accessible to visitors." But parks without "accessible areas" will be closed, and additional sites could shutter if damage is done to park resources or garbage builds up during the shutdown.
The park service oversees 400 sites, including large national parks such as Yellowstone and Grand Canyon, national battlefields and national monuments like the Statue of Liberty.
