A government shutdown could set the U.S. back "months, if not years" in its ongoing air traffic controller staffing shortage, the head of the workforce's union told ABC News Thursday.
Close to 1,000 trainee air traffic controllers will be off the job next week if Congress doesn't reach a deal to fund the government. They have until the end of the day Sept. 30; the government shuts down 12:01 a.m. ET on Oct. 1 if they can't strike a deal.
Roughly half of the controllers that would be furloughed are currently in training at the Federal Aviation Administration's facility in Oklahoma City. A shutdown would close that school and send its students home.
MORE: Government shutdown would mean fewer controllers, potential flight disruptions"A few-day shutdown will incur months, if not years of delay to the health of the staffing in our facilities," Rich Santa, president of the National Air Traffic Controllers Association, said in an interview with ABC News.
This echos comments made by Transportation Secretary Pete Buttigieg in a press conference Wednesday, who said, "A shutdown lasting a few days could mean we will not hit our staffing and hiring targets next year."
The U.S. currently employs 1,200 fewer controllers than it did 10 years ago -- despite more planes and travelers in the skies. Santa called the current staffing levels "critically low" and told ABC News that any interruption would likely lead to a restart in training.
"It's just appropriate and more sincere to start from the beginning and give every opportunity to learn at the pace that you're supposed to learn it," Santa said.
Santa also expressed concerns for the more than 13,000 air traffic controllers who would stay on the job during a shutdown without getting paid, recalling the 35-day shutdown in 2018 as "immensely difficult."
MORE: As government shutdown approaches, agencies tell workers that furloughs are coming"The mortgage payments are still due. The car payments are still due. Utilities still need to be paid," Santa said. "People having to get loans to pay their bills while they're still expected -- and still proudly -- as air traffic controllers going to work as civil servants and ensuring that the airspace is safe."
And on top of the stresses to the air traffic controllers, Santa said travelers could also see impacts to their flights and vacations if a government shutdown isn't averted.
"Connections could be missed," he said. "Delays will be increased. Cancellations, although we don't control any of that, might be a part of [passengers'] vacation plans."
Santa called on Congress to pass legislation to avoid a shutdown -- saying it would make the already stressful job of an air traffic controller even more challenging.
"If it goes more than a day or two, the challenges get exponentially harder for our members, for the industry and for the flying public," he said. "We want this over quick. Ultimately, we don't want it to happen at all."