Flightplan.com had all of the notams in their system up until the feds computers crapped out. Any updated info that pertained to my flight I got with several phone calls to destination FBO and from company. Although a pain in the behind to do the extra work, still able to conduct flight. If I was VFR it would be a little harder due to making sure no TFR’s, but I have been told that is a different system. Absolutely, positively no reason to totally shut down US airspace. The Canadians didn’t shut their airspace down during their notam glitch!