Over 9,000 flights were canceled or delayed and several major airports were temporarily closed Over 9,000 flights were delayed or canceled across the US on Monday and Tuesday, according to Federal Aviation Administration (FAA) data. The disruptions were triggered by a staffing shortage of air traffic controllers caused by the ongoing partial government shutdown. The shutdown began on October 1 after Democrats and Republicans failed to agree on a spending bill. While most federal workers are furloughed, air traffic controllers are deemed essential and must work without pay during the shutdown, although back pay is guaranteed. However, Transportation Secretary Sean Duffy confirmed a higher rate of controllers calling in sick since the shutdown began. The National Air Traffic Controllers Association (NATCA) union, which represents 20,000 air traffic controllers, said it is working with the FAA to mitigate disruptions in the National Airspace System. “It is normal for a few air traffic controllers to call in sick on any given day, and this is the latest example of how fragile our aviation system is in the midst of a national shortage of these critical safety professionals,” NATCA said in statement on Monday. “NATCA has consistently warned that the controller staffing shortage leaves the system vulnerable, and today’s events underscore the urgent need to accelerate training and hiring,” it added. The statement warned that a government shutdown places an unnecessary strain on an already overstretched workforce. It recalled that during the 2019 shutdown, many controllers were forced to take second jobs to pay their bills, leading to significant stress and fatigue. The shutdown also impacts the Essential Air Service, a program that funds flights to smaller airport, he said, warning that its funding could run out. During a 35-day government shutdown in 2019 under President Donald Trump’s first term, a spike in absences among controllers and TSA officers led to extended checkpoint waits and forced authorities to slow air traffic, particularly in New York, increasing pressure on lawmakers to end the standoff.Airports in Denver, Newark, and Burbank were among those most affected by the disruptions early this week.