Major U.S. airports experienced flight delays Monday night due to staffing shortages, following reports from Transportation Secretary Sean Duffy of more air traffic controllers calling in sick amid the government shutdown.

The disruptions affected key hubs, including Los Angeles-area airports, Newark, and Denver, raising fears of a repeat of the severe travel strains seen during the 2019 shutdown.

California Gov. Gavin Newsom criticized the shutdown for the delays, while Duffy blamed Democrats, highlighting partisan tensions over the standoff.

Air traffic controllers and TSA agents are essential workers, with over 13,000 controllers expected to work without pay, potentially worsening staffing issues, Axios has reported.

Duffy reassured travelers that airspace safety remains a priority, though delays may continue due to the strain on personnel.