We used to have a pretty solid Air Defense network - that went away decades ago.
At one time, the American skies were pretty well defended with radars, Nike Missile Batteries, BOMARC, Hawk, F-101s, F-102s, F-106s, etc.
That disappeared in the 1970s and we’ve assumed away the threat since then.
We do have a few anti-missile missiles in Alaska and California - but it is not many, less than 100. That will be easily overwhelmed with a mass launch.
With China, Russia, Iran, North Korea, Venezuela, Cuba, mystery drones (not the ones in New Jersey) and other threats, the bad people know the American airspace is porous at best.
No we don’t have radars giving 100, 90, 50, or 30 percent coverage, the primary method of air traffic surveillance is trusting everyone will use ADS-B to squawk their position. Well if you don’t squawk on ADS-B, you’re basically a ghost and unseen.
President Trump understands the grave weaknesses and is now doing something about it, “Iron Dome for America”.
