"The FAA is still working to fully restore the Notice to Air Missions system following an outage," FAA said in a statement.

"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," read the statement.

American Air tweeted: "The Federal Aviation Administration (FAA) is experiencing a nationwide system outage that affects all airlines. We're closely monitoring the situation and working with the FAA to minimize customer disruptions."

United Airlines also said they have temporarily delayed the domestic flights until they heard more from the FAA.