Transportation Secretary Pete Buttigieg said a government shutdown would come "at exactly the wrong moment" as the department works to address the ongoing air traffic controller shortage.
While the Department of Transportation met its hiring goals this year for air traffic controllers, Buttigieg noted if a government shutdown occurs at the end of the month, it would "stop us in our tracks" as the Federal Aviation Administration works to train new controllers.
If a government shutdown occurs, controllers currently working in towers would stay on the job, but training of new controllers at the FAA facility in Oklahoma would pause.
"We now have 2,600 air traffic controllers in training. A government shutdown would stop that training. Even a shutdown lasting a few weeks could set us back by months or more because of how complex that training is," Buttigieg said during a hearing in front of the House Transportation and Infrastructure Committee on Wednesday. "We cannot afford that kind of politically driven disruption at the very moment when we finally have those air traffic control workforce numbers headed in the right direction."
MORE: FAA looks to require cockpit technology to reduce close callsThe aviation industry is still attempting to address the marked increase in air travel as it rebounds from the lows of the pandemic.
Last week, the FAA announced it would extend a waiver that allows airlines to fly fewer and larger planes to New York City airports because the number of certified controllers in the area is "not sufficient" to handle normal traffic levels.
"The industry is ramping back up from the pandemic, during which a number of people ... were either retired or were laid off layoff," National Transportation Safety Board Chairwoman Jennifer Homendy said earlier this year. "A new workforce is coming in that needs to be appropriately, adequately trained. Some who were out during the pandemic also need to be retrained."
The United States currently employs 1,200 fewer fully certified controllers than 10 years ago, despite more planes and passengers in the skies, according to the National Air Traffic Controller Association.
Congress faces a Sept. 30 deadline to pass spending bills or else risk a government shutdown. Leaders in both parties are signaling an increased willingness to punt the deadline to fund the government to later this year by passing a stop-gap funding bill to keep the government funded past the Sept. 30 deadline.
ABC News' Gio Benitez and Sam Sweeney contributed to this report.