The Federal Aviation Administration lifted a nationwide ground stop issued on Nov. 13 after a communications outage affected 22 air-route traffic-control centers across the United States. Aircraft already airborne were allowed to land during the disruption, while departures were halted or restricted and some international, Alaska and Hawaii flights continued on a limited basis. FlightAware reported more than 10,000 delays and over 3,200 cancellations by 6:45 p.m. Eastern, with more than 30,000 departures and arrivals scheduled for the rest of the day. The halt was the first nationwide departure stoppage in the United States since a computer system failure in January 2023. Airline stocks and major U.S. index ETFs fell in after-hours trading, while Palo Alto Networks, CrowdStrike and Zscaler gained. Homeland Security Secretary Markwayne Mullin said there was no reason to suspect a national security threat and described the incident as a telecommunications outage. The cause remained unconfirmed, although reports cited an update to a private L3Harris Technologies communications network that allegedly caused a system reboot and outage. Microsoft said its separate global outage was not a factor, and ASI said the disruption was unrelated to the FAA's SMART artificial-intelligence system. The incident prompted calls for a full investigation and renewed scrutiny of aging air-traffic-control infrastructure. Passengers whose flights are canceled are generally entitled to refunds under Department of Transportation rules, while meals, hotels, transportation and partner-airline rebooking depend on carrier policies when disruptions are outside their control.