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. That means a vast majority of employees who keep U.S. airports and air travel running are working without pay until the government reopens. Here’s what to know about the shutdown and its potential impacts on your travel plans:Flying during a shutdownTravelers 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. National Parks will remain mostly open 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.