More than 6,400 flights were canceled and over 8,000 delayed on Saturday as the US aviation system struggled to recover from a nationwide ground stop. Authorities traced the disruption to a router problem during a telecommunications upgrade carried out by contractor L3Harris, although the exact cause remains under investigation.

US air travel disruptions are expected to continue until late Sunday, November 15, according to Federal Aviation Administration (FAA) Administrator Bryan Bedford, as airlines work to restore normal operations following a nationwide shutdown that affected thousands of flights.

According to FlightAware figures cited by Reuters, airlines had canceled more than 6,400 flights and delayed over 8,000 across the United States by 9:35 p.m. Eastern Time on Saturday. That followed approximately 9,200 cancellations and 7,500 delays on Friday. A further 875 flights scheduled for Sunday had already been canceled at the time of the report.

The FAA issued a nationwide ground stop on Friday, November 13, halting almost all departing flights for nearly five hours after communication problems affected multiple air traffic control centers. The agency said the decision was taken as a precaution to protect aviation safety.

L3Harris router identified as possible source

US Transportation Secretary Sean Duffy said the disruption may have originated during routine maintenance performed by L3Harris, a long-standing FAA contractor responsible for the telecommunications network used to manage US airspace.

The work involved replacing aging copper telephone lines with fiber-optic connections, transitioning from analog technology to digital systems. During the process, a router reportedly began flooding other devices across the network with more than 1,000 connection attempts every four to five seconds.

According to officials, the resulting data overload affected communications between controllers and aircraft, as well as radar feeds. The problem impacted 17 of the FAA's 22 en route air traffic control centers.

Duffy said investigators have not yet determined whether the failure resulted from an installation mistake, human error or a defective router. L3Harris confirmed it is cooperating with the FAA investigation.

Authorities have also said they do not believe the incident was caused by a cyberattack. The FAA reported that no control center completely lost communications, although the instability was serious enough to trigger the nationwide ground stop.

Aging infrastructure raises further concerns

The incident has renewed questions about the condition of the US air traffic control system, which still relies on aging telecommunications infrastructure. Officials acknowledged that some equipment being replaced dates back approximately 25 years.

The disruption also highlighted the challenges of modernizing the network while maintaining continuous operations. Duffy said the government would review when maintenance work is carried out to reduce the risk of similar incidents.

The Transportation Department has received $12.5 billion in congressional funding for modernization, while Duffy has called for an additional $50 billion to upgrade air traffic control systems and airport infrastructure.

Student pilot caught in the shutdown

One of the most striking episodes involved a student pilot on his first solo cross-country flight near Fort Worth, Texas. After being informed of the nationwide ground stop and instructed to land, he told an air traffic controller: “Ma'am, I'm a student pilot. Honestly, this is my first time doing solo cross-country, and I don't know what to do.”

The controller calmly guided him back toward Hicks Airfield, helping him avoid nearby aircraft, including two helicopters. The student landed safely.

The episode illustrated the operational uncertainty created by the shutdown, even though authorities confirmed that aircraft already in the air were brought down safely.

Although the FAA has confirmed that the system is stable and the nationwide ground stop has been lifted, the backlog of canceled flights, displaced aircraft and crews continues to affect airline schedules. Travelers across the United States should therefore expect delays and cancellations through Sunday, with a return to largely normal operations anticipated only by late in the day.