Do USAF fighter jets go supersonic over land? Does the US Air Force operate supersonic fighter jets over land?

I heard that the FAA banned supersonic flight over America due to the shockwaves creating loud booms and breaking windows on the ground, therefore the Concorde only operated over the Atlantic Ocean.

However, is the US Air Force allowed to operate supersonically over land? How about in training missions, or drills, or a real event? Did they go supersonic during 9/11?
Generally speaking, FAA does not allow supersonic flights over land except in special restricted military flight corridors. These are called High Altitude Supersonic Corridor (HASSC) in the US. For example, the one near Edwards AFB is:



NASA also mentioned about supersonic flights:


  The F-18s flew in Edwards' High Altitude Supersonic Corridor at 32,000
  to 40,000 feet for the supersonic runs.


However, I read that FAA's jurisdiction is only until 60,000 feet, hence above this altitude, there are no speed limits:


  According to the FAA regulations the controlled airspace extends up to
  60,000 feet. Anything flying above may fly at “unlimited speeds.”




During 9/11 attacks, US Air Force had its aircraft fly supersonically over mainland.