While a federal government shutdown would halt some government operations, air traffic controllers and security screeners at airports would be deemed essential employees and would continue working to keep flights and passengers flowing.

A federal shutdown could take effect Saturday if lawmakers don’t reach a deal to keep government funded.

But because essential employees including the Federal Aviation Administration’s air traffic controllers and Transportation Security Administration officers would stay on the job, air travel would be able to continue — at least initially — without disruption.

That’s a key concern for many as the busy holiday travel season ramps up. But the essential employees “would continue working without pay in the event of a shutdown,” according to a TSA spokesperson.

Furloughed federal employees and essential employees who are required to work during a shutdown are guaranteed retroactive pay. But if there is a shutdown, it may be unclear how long that could last.

“While our personnel have prepared to handle high volumes of travelers and ensure safe travel, an extended shutdown could mean longer wait times at airports,” according to TSA, which has about 1,700 employees in Atlanta.

That’s because if workers miss a paycheck, it makes it harder for them to pay their bills and to continue to come into a job without getting paid.

During the federal shutdown that started during the first Trump administration in late December 2018 and continued into January 2019, many travelers ended up waiting in security lines as long as an hour and a half at Hartsfield-Jackson, causing some to miss their flights.

Some federal workers started calling out from the job or quitting during that shutdown after they missed their first paycheck and faced personal hardships. TSA said its unscheduled absence rate was 7.6% on the Monday after workers missed their first paycheck, more than twice the typical rate. During that shutdown period, Delta Air Lines advised getting to the Atlanta airport three hours early.

And some federal work would stop during a shutdown, including air traffic controller hiring and training, budgeting and administrative work. That can have longer-term effects for those agencies and their work.