Transportation Secretary Sean Duffy said on Oct. 6 that the government shutdown is adding stress to already overworked and understaffed air traffic controllers, as some areas have seen an uptick in controllers calling in sick.

Though Duffy said the nation's airspace remains safe, he noted that some air traffic control facilities were experiencing an increase in sick calls ‒ with some missing as many as 50% of employees on any given day since the shutdown started last week. Duffy warned that understaffed facilities could result in flight delays and cancellations as the Federal Aviation Administration limits capacity through some sectors of the airspace.

Duffy said controllers, who are mandatory federal employees, are worried about how to pay their bills while keeping the airspace safe. Thousands of controllers are expected to show up for work during the shutdown. They are not being paid and are set to miss their first paycheck on Oct. 14.

“Now, what they think about as they’re controlling our airspace is, how am I going to pay my mortgage? How do I make my car payment? I have a couple kids at home. How do I put food on the table? I’m working six days a week," Duffy said during a news conference at Newark Liberty International Airport in New Jersey.