Router failure causes nationwide suspension of all United States flight departures

A technical failure during telecommunications modernization caused a nationwide suspension of all United States flight departures for over four hours on Friday, November 14, 2026. The disruption occurred after a router failure during routine work to replace old copper cables with fiber optic cables. The Federal Aviation Administration (FAA) lifted the flight suspension at 8:15 p.m. EST on Friday, November 14, 2026.

System instability and technical causes

The disruption was caused by a router failure during routine work to replace old copper cables with fiber optic cables. The contractor performing the work was L3Harris. According to officials, the faulty router sent over 1,000 connection requests every four to five seconds, which overloaded other flight control system devices. This technical malfunction caused communication issues with aircraft and a loss of radar data.

FAA Administrator Bryan Bedford said that instability spread through the system, necessitating the precautionary decision to halt departures. US Secretary of Transportation Sean Duffy said the router failure caused communication and radar issues and noted that officials are investigating if the cause was contractor error or a defective component. Investigators are specifically looking into whether the issue involved a defective Cisco router manufactured between 2001 and 2006.

Impact on flight schedules

The disruption resulted in significant cancellations and delays across the aviation network. Reports on the total number of cancellations for Friday vary. One source reported 12,500 flights cancelled on Friday, while other reports cited 12,000 flights cancelled on that day. At Montréal-Trudeau, 61 flights were cancelled on Friday, according to one report.

The impact continued into the following day. Reports regarding Saturday cancellations vary significantly. One source reported 6,400 flights cancelled on Saturday evening, while another reported 5,000 flights cancelled during Saturday afternoon. A third source reported 3,500 flights cancelled on Saturday and 2,000 delays occurring on the same day. At Montréal-Trudeau, 40 flights were cancelled on Saturday.

Passengers experienced significant disruptions at various terminals. Lisa Beraid, a passenger at LaGuardia Airport, described the situation at the airport as a total mess.

Modernization and historical context

This incident is the second nationwide flight suspension in the United States since the September 11, 2001, attacks. The disruption occurred as the aviation system undergoes significant infrastructure upgrades. The US Congress previously approved $12.5 billion for system modernization. To date, 69% of FAA copper communication cables have been replaced with fiber optics.

Glossary

• Federal Aviation Administration (FAA) — The Federal Aviation Administration (FAA) is the agency that regulates unmanned aircraft systems in the National Airspace System. It is responsible for approving commercial unmanned aerial system (UAS) licenses and managing aircraft registration requirements.
• L3Harris — L3Harris Technologies, Inc. is an American technology company and defense contractor. It provides information technology services and produces products for various sectors, including command and control systems and avionics.
• LaGuardia Airport — LaGuardia Airport is an airport located in New York City. It is the 20th busiest airport in the US and handles 23% of NYC air traffic.