Unlike other military fixed-wing aircraft, the AC-130 relies on visual targeting and operates at low-altitude (roughly 7,000 ft). The United States Air Force is the sole user, using the current AC-130U Spooky II variant
This scary AC-130U (or Spooky II) is seen here entering runway 33 via Charlie for departure! You can clearly see the three guns on the side (a 25 mm General Dynamics cannon, a 40 mm Bofors cannon, and a 105 mm M102 howitzer)!! Scary enough??