US Air Traffic Control Crisis: How an Overloaded Communications System Grounded Flights Nationwide
The Federal Aviation Administration (FAA) has lifted its nationwide ground stop after an overloaded, aging communications system disrupted air traffic control operations across the United States on Nov. 13, grounding departing flights for more than four hours. Although the agency tested its systems before allowing departures to resume at 8:15 p.m. Eastern time, thousands of cancellations and delays continued to affect air travel, with disruptions expected to extend into Saturday, Nov. 14.
Transportation Secretary Sean Duffy attributed the failure to overloaded routers and outdated equipment in the U.S. air traffic control network. Homeland Security Secretary Markwayne Mullin said officials were investigating the technical problems, while the contractor behind the FAA’s new SMART artificial intelligence system denied that its technology was connected to the outage.
Scale of Nationwide Flight Disruption
The ground stop disrupted domestic and international aviation operations, affecting passengers, airlines and airport operations. According to flight-tracking platform Flightradar24, 4,042 aircraft were airborne and heading toward U.S. airports when the FAA issued the order at 3:54 p.m. Eastern time on Nov. 13. Aircraft already in the air were generally allowed to continue toward their destinations, although some flights faced diversions.
At least 600 flights were diverted, according to flight-tracking data. The disruption also affected international services. Air Canada canceled flights to and from the United States for the remainder of the evening, while Canada’s NAV CANADA warned that delays could continue after U.S. airspace operations resumed. The FAA lifted the nationwide ground stop at 8:15 p.m. Eastern time. However, airlines still had to reorganize aircraft, crews and departure schedules, extending delays beyond the period of the order.
At a Friday evening news conference, Duffy attributed the disruption to overloaded routers and switches in the legacy air traffic control network. He said the equipment had begun producing inconsistent data, prompting officials to suspend departures as a safety precaution. “We have old switches, old routers. We use 1980s little copper lines. It’s an old system that went down and went down everywhere. It got overloaded.”
The telecommunications problems affected the systems air traffic controllers rely on to exchange information and coordinate aircraft movements. The FAA’s decision to halt departures was intended to prevent aircraft from operating without reliable communications support. Officials described the incident as an extraordinary circumstance. The precise technical sequence that caused the failure remained under investigation.
New Technology Raises Questions About Compatibility
The outage occurred as the FAA continued integrating new technology into its national air traffic control network. Homeland Security Secretary Markwayne Mullin said officials were examining whether newer equipment and existing infrastructure had become incompatible.
Multiple sources told CBS News that an update to the private network connecting the air traffic control system triggered the failure. However, officials had not publicly established the precise technical sequence that caused the disruption.
The FAA had also been rolling out a new artificial intelligence tool called the Situational Management Awareness and Routing Tool (SMART), designed to help manage airspace congestion and improve flight routing. However, there was no confirmed evidence linking SMART to the outage. The company behind the system denied that its product or its integration with the FAA caused the disruption.
Duffy Calls for $50 Billion to Modernize Air Traffic Control
The communications failure renewed pressure on Congress to fund a comprehensive overhaul of the U.S. air traffic control system. Duffy described the incident as an emergency and called for $50 billion in funding to replace outdated infrastructure. “This is an emergency,” he told reporters. “I want Congress to give us emergency funding. This is bipartisan. This is American. I want $50 billion.”
He warned that similar disruptions could occur without substantial investment in replacing the outdated equipment. The funding request comes as the Trump administration pursues a broader modernization effort involving telecommunications equipment, radar systems, software and air traffic control facilities.
Previous Outages Raised Concerns About Aging Infrastructure
The nationwide disruption followed earlier air traffic control problems that raised concerns about the reliability of U.S. aviation infrastructure. In May 2025, air traffic controllers at the Denver Air Route Traffic Control Center lost communications with aircraft for approximately 90 seconds and had to switch to backup frequencies. The incident followed earlier communications problems at a Philadelphia facility responsible for handling flights in and out of Newark Liberty International Airport.
In January 2025, a midair collision between an American Airlines passenger jet and a U.S. Army helicopter near Washington, D.C., killed 67 people. The accident prompted further scrutiny of aviation safety and air traffic management, although it was separate from the November communications failure. The Trump administration subsequently advanced plans to modernize the national air traffic control system, including upgrades to communications networks and other critical equipment.
The FAA’s investigation will determine what triggered the Nov. 13 communications failure, how the disruption spread across air traffic control facilities and what infrastructure upgrades are needed to reduce the risk of similar incidents. The findings could also influence the timeline and funding priorities of the government’s air traffic control modernization program.
