Delays and cancellations are likely continue for US air passengers, even as airports are slowly returning to normal after domestic flights were grounded this morning because of a system outage at the Federal Aviation Administration (FAA) .
The FAA is the US government agency which oversees many aspects of America's aviation, including air traffic management.
The issue affected the Notice to Air Missions (NOTAM) system, which provides pilots with real-time information about changes and potential hazards on flight routes.
"The FAA is still working to fully restore the Notice to Air Missions system following an outage. The FAA has ordered airlines to pause all domestic departures until 9 a.m. Eastern Time to allow the agency to validate the integrity of flight and safety information," it later added.
A little over two hours after the initial reports of the issue, the FAA has now stated that operations were being restored and flights were taking off -- but many airlines and airports warn that disruptions are likely to continue across the day.
"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," said the statement.
The exact nature of the computer issue is yet to be disclosed, but the White House has said there's currently no evidence it's due to a cyberattack. The importance of the NOTAM system to flight safety meant that, for a period of time, all flights within the US were grounded. Airports and air carriers have warned travelers that they should expect delays.
"The ground stop has been lifted. Flights are beginning to board and prepare for departure. Residual delays or cancellations will likely continue throughout the day as a result of this morning's outage. Passengers are still urged to check flight status before leaving for airport," warned O'Hare International Airport.
"The FFA system that sends out important real-time flight hazards and restrictions to all commercial airline pilots -- Notice to Air Missions (NOTAM) -- is currently suffering a nationwide outage. United has temporarily delayed all domestic flights and will issue an update when we learn more from the FFA," United Airlines said earlier today in a statement.
Following the FAA nationwide ground stop being lifted, the company said it has started resuming flights. "Efforts are underway to minimize impacts to our customers and our operation."
"The FAA has lifted the ground stop but cancelations and delays are expected through today as airlines work to restore their regular operations. "Please continue to check in with your airline before heading to AUS," the airport added, following the initial disruption.