starting to see some explanations for what's going on

https://www.wsj.com/us-news/faa-temporarily-halts-flights-ac...

> The outage appears to be affecting a telecommunications network overseen by L3Harris Technologies, according to people briefed on the matter. The network handles crucial radio frequencies that air-traffic controllers use to communicate with pilots, the people said. It wasn’t immediately clear whether the outage also affected the radar feeds that controllers use to keep aircraft safely separated in the skies.

https://www.cbsnews.com/news/faa-issues-nationwide-ground-st...

> An update to the private communications network that connects America's air traffic control system caused the system to reboot, leading to a crash and a communications outage, multiple sources told CBS News. The system is operated by L3Harris, which did not immediately respond to CBS News' request for comment.