United Airlines canceled its remaining domestic flights to and from Newark for Monday, September 21, 2026, after an air traffic control communications infrastructure failure caused major disruptions across the northeastern United States. According to ABC7, the decision covers United’s mainline services and regional operations under the United Express brand, while the airline said it would prioritize remaining international departures as it worked to stabilize operations.

Throughout the day, restrictions affected all three major New York-area airports—John F. Kennedy, LaGuardia and Newark Liberty—as well as Philadelphia and Teterboro in New Jersey. The Federal Aviation Administration (FAA) restricted incoming traffic following a communications outage at the Philadelphia Terminal Radar Approach Control facility, known as Philadelphia TRACON. According to AeroTime, approximately 90 flights were diverted to other airports immediately after the disruption began.

FAA Administrator Bryan Bedford explained that the primary communications circuit had failed. When the system switched to its backup, officials discovered that a fiber-optic cable between New Brunswick and Newark had been severed during construction work. As AeroTime reported, the simultaneous loss of both connections interrupted the normal transmission of radar data and radio communications, forcing controllers to reduce traffic until safe operating conditions could be restored.

According to Reuters, US Transportation Secretary Sean Duffy said the cable had been accidentally damaged by a construction crew working for rail operator Amtrak. Telecommunications provider Verizon confirmed that the damage to its fiber-optic cable was located alongside an Amtrak rail line. The disruption also spread to Boston, where incoming flights were temporarily halted because of additional traffic pressure.

Operations recovered gradually, with the pace varying between airports. According to ABC7, JFK and LaGuardia began accepting flights again during the afternoon, subject to restrictions, while problems persisted at Newark. CBS Philadelphia reported that the ground stop affecting flights bound for Philadelphia was lifted at around 5 p.m. local time, although a ground delay program remained in effect. FlightAware data cited by CBS showed that Philadelphia had recorded nearly 400 delays and approximately 200 cancellations by that time.

The arrival of world leaders and diplomatic delegations for the United Nations General Assembly in New York added further pressure. Reuters reported that the FAA said incoming traffic at affected airports would not resume until safe operating conditions could be confirmed.

Philadelphia TRACON was also involved in serious communications outages that disrupted Newark operations in 2025. As Reuters previously reported, responsibility for part of Newark’s air traffic control operations was transferred from New York to Philadelphia in 2024 to help address controller shortages. Following last year’s outages, a review of that decision was launched, covering backup system reliability, staffing levels and operational resilience. The latest disruption has renewed attention on the modernization of US air traffic control infrastructure, for which Congress approved $12.5 billion last year.