Long story short - FAA had to ground all flights nationwide starting at 6:30am this morning due to a computer systems outage of the notification system they use
The FAA is working to restore its Notice to Air Missions System. We are performing final validation checks and reloading the system now. Operations across the National Airspace System are affected. We will provide frequent updates as we make progress.— The FAA ✈️ (@FAANews) January 11, 2023
The most recent update from a couple minutes ago is that some flights are resuming at Atlanta and Newark, not because systems are restored but in order to reduce congestion
Update 4: The FAA is making progress in restoring its Notice to Air Missions system following an overnight outage. Departures are resuming at @EWRairport and @ATLairport due to air traffic congestion in those areas. We expect departures to resume at other airports at 9 a.m. ET.— The FAA ✈️ (@FAANews) January 11, 2023
And while this is good news, this overall event is not something the airline industry can easily handle. From crew staffing to needing planes to take certain flights to get planes at gates in order for future departures, any kind of ripple to the system here snowballs. And to cancel at least 3 to 4 hours of all flights for all airports and all airlines is going to be felt for a while, with the impact likely being felt for the remainder of the week, if not longer.
If you're due to fly anywhere this week, expect headaches, and may the odds be ever in your favor.