• Ground stop: All flights in the United States are grounded until further notice, “due to extraordinary circumstances and for reasons of safety,” the Federal Aviation Administration said.
• Cause not yet known: The reason for the ground stop was not immediately clear, but an FAA spokesperson said there is a communications problem impacting Air Route Traffic Control Centers, which handle flights going across the country.
• Rare instance: The last time there was a nationwide ground stop was in January 2023, when a pilot notification system went down. Prior to that, the last nationwide ground stop was issued after the September 11, 2001, attacks.
