Transportation Secretary Sean Duffy said Sunday that air traffic controllers “are wearing thin” amid the ongoing government shutdown.

“The controllers are wearing thin,” Duffy told Maria Bartiromo on Fox News’s “Sunday Morning Futures.” “And again, they’re taking second jobs, they’re out there looking, ‘Can I drive Uber, can I find another source of income to make ends meet?’”

Duffy also noted that 22 air traffic controller staffing triggers occurred at airports across the country on Saturday, the highest number to date during the shutdown. Air traffic controllers are working without pay during the funding lapse.