The Federal Aviation Administration (FAA) informed on Wednesday that the ground stop order on all flights has been lifted and normal air traffic operations are resuming gradually across the country.
Over 4,300 flights were grounded and more than 700 were cancelled after the FAA witnessed a system failure during the day.
The Notice to Air Missions (NOTAM) system was not being able to provide updated information to the flights, which has forced the FAA to ground all flights.
"Normal air traffic operations are resuming gradually across the U.S. following an overnight outage to the Notice to Air Missions system that provides safety info to flight crews.
"The ground stop has been lifted. We continue to look into the cause of the initial problem," the FAA informed via Twitter.
White House Rules Out Cyberattack
The US President Joe Biden was briefed on the flight situation on Wednesday evening after which the White House released a statement saying that there was "no evidence of a cyberattack."
The FAA had earlier ordered airlines to pause all domestic departures after its pilot alerting system crashed and the agency had to perform a hard reset around 2 a.m., officials said.
The FAA said shortly before 8:30 a.m. departures were resuming at Newark and Atlanta airports.
The FAA is expected to implement a ground delay program in order to address the backlog of flights halted for hours. Flights already in the air had been allowed to continue to their destinations during the ground stop.
