The US Federal Aviation Administration (FAA) said Friday it was lifting a nationwide ground stop on departing flights after an outage disrupted air traffic operations.
Some 4,700 flights were cancelled, while Southwest and JetBlue said they would cancel the rest of their US flights for the day.
Three sources linked the outage to a telecommunications network operated by L3Harris that handles air traffic control radio frequencies.
President Donald Trump said the halt did not appear to be linked to a cyberattack or artificial intelligence. Homeland Security Secretary Markwayne Mullin said there was no reason for the public to be afraid.
Friday’s disruption marked the second nationwide ground stop on all departures since the September 11, 2001 attacks.
