The Federal Aviation Administration lifted a nationwide ground stop Friday evening after a failure involving aging air traffic control equipment disrupted flights across the United States for approximately five hours. The shutdown affected thousands of departures and potentially more than a million travelers, leaving airlines facing widespread cancellations, diversions and delays. Federal officials attributed the disruption to overloaded communications equipment that produced inconsistent radar and communications data. The incident marked the longest nationwide ground stop in approximately 25 years.

Transportation Secretary Sean Duffy said the problems began when switches and routers became overwhelmed with data while newer technology was being introduced into the air traffic control system. The equipment began producing inconsistent information, prompting the FAA to halt departures over concerns about the reliability of communications and radar systems. Duffy said the agency took the precaution to maintain the safety of aircraft and passengers. The exact technical sequence that caused the failure remained under investigation Friday evening.

Homeland Security Secretary Markwayne Mullin said investigators had found no indication of a cyberattack or other malicious activity. Officials said more than 3,000 flights landed safely during the disruption, while hundreds of other aircraft were diverted or returned to their departure airports. Mullin emphasized that authorities had not identified evidence suggesting passengers were deliberately placed in danger. Investigators were continuing to examine how the new and existing systems interacted.

In a statement Saturday, L3Harris Technologies, the defense contractor involved in modernizing the FAA's aging telecommunications infrastructure under the Trump administration's broader air traffic control overhaul, said it had "completed more than 70%" of the planned transition from copper wiring to fiber optics. Transportation Secretary Sean Duffy identified L3Harris as the contractor performing upgrades at a remote FAA facility when Friday's nationwide outage began. Investigators are examining whether contractor error or faulty equipment caused the failure, with no final determination announced. L3Harris said it is cooperating with the FAA's investigation.

The disruption spread across major aviation hubs, including airports in Washington, Chicago and Los Angeles. Aviation analytics company Cirium reported at least 827 flight diversions, including aircraft that returned to their original departure airports. Airlines began preparing recovery operations as the FAA authorized departures to resume, although aircraft and flight crews remained displaced across the country. Airlines warned that cancellations and delays could continue as flight schedules were gradually restored.

The nationwide failure has renewed scrutiny of the country's aging air traffic control infrastructure and the challenges of modernizing it without disrupting operations. Duffy acknowledged that he could not guarantee a similar failure would not occur again, while officials expressed confidence that operations would stabilize before Thanksgiving travel. The FAA's last nationwide ground stop occurred in January 2023, when a computer system failure forced airlines to suspend departures. Investigators have not announced a final determination of Friday's technical failure.

Major airlines introduced temporary travel accommodations as passengers faced widespread disruptions. Delta Air Lines issued a systemwide travel waiver for flights scheduled November 13 and 14, allowing eligible customers to change their reservations without additional fees or fare differences for travel through November 21, provided they remained in the same cabin. United Airlines also waived change fees and fare differences for affected passengers rebooking on United-operated flights departing by November 20, subject to restrictions on destinations and cabin classes. American Airlines offered eligible travelers at affected airports a one-time change without a change fee, allowing passengers originally scheduled to travel November 13 or 14 to reschedule their flights through November 17.

The airlines also provided options for passengers unable or unwilling to continue their original itineraries. Delta allowed travelers to cancel reservations and receive credits toward future flights, while American offered eligible passengers the option to cancel and request refunds. American required changes under its waiver to be booked by November 14, while United and Delta provided longer rebooking windows. Despite the accommodations, passengers continued to face uncertainty as airlines worked to reposition aircraft, restore flight schedules and return crews to their assigned routes following the nationwide shutdown.