"This is about where’s the pressure and how do we alleviate the pressure," Transportation Secretary Sean Duffy said.

The Federal Aviation Administration will reduce air traffic at many busy airports to maintain safety during the government shutdown, which has led to staffing shortages of air traffic controllers.

Duffy said the FAA will reduce flight capacity across the nation's airspace starting on Friday if air traffic controllers continue to be unpaid.

The crash near the Louisville Muhammad Ali International Airport marked the deadliest accident in UPS Airlines history.