https://www.cnn.com/2019/01/25/us/ai...faa/index.html
Apparently, air traffic controllers were already working overtime due to understaffing, and now just a slight increase in sick leave has left them incapable of handling the volume of air traffic.
It doesn't sound as if this is a coordinated sick out (although who could blame them, what with not having been paid in a month). There is a very high level of viral illness in the country currently, and I bet that this is from controllers who have a virus, who beforehand might have just gone to work sick, deciding that it's just not worth it, and taking a sick day. I'm sure that they're also struggling with that choice, because they know that if they call in sick, it just puts even more stress on their already overworked colleagues.
So flights are backing up in the mid-Atlantic area, and this will of course have ripple effects all across the country. This is the quickest way to put pressure on our government to end the shutdown - if the planes cannot fly.