If Congress can't keep the government open, the consequences for air travel could be painful.
And it's pain that Transportation Secretary Pete Buttigieg says can't come at a worse time for an industry just getting back on its feet.
"We've done a lot of good work," Buttigieg said. "We've pushed the airlines very hard, which is why this year, we finally got cancellations back below 2%, they're actually below their pre-pandemic levels. But that progress is immediately threatened."
But what exactly happens if federal funding lapses come Saturday?
Right off the bat we know federal workers will be furloughed or forced to work without pay.
That includes roughly 73,000 air traffic controllers and Transportation Security Administration officers.
These are the services that would be impacted by a government shutdown
From air travel to a program that makes sure newborns are being fed, a government shutdown would have wide-ranging consequences.
During the shutdown of 2018 and 2019, many TSA agents and air traffic controllers called out sick, causing crippling flight delays and prompting long waits in security screening lines.
A shutdown would also mean no pay for air traffic controllers, adding stress to an already-demanding gig. And it could hamper efforts to address an existing controller shortage.
The union for American Airlines pilots is warning its members "Our national aviation system is already under pressure due to overly aggressive airline scheduling, inadequate air traffic control staffing levels, and an influx of less experienced employees. Never allow yourself to be rushed in the performance of your duties."
And to make matters more complicated, Congress is also staring down a separate Saturday deadline to reauthorize the Federal Aviation Administration. Lawmakers could miss that one too, putting significant stress on an already strained system.
