Why the Army? Shouldn’t this be the USAF?
The Army has traditionally had the tasking of coastal defense of the country and in the modern era they operated the anti-aircraft missiles along with artillery.
Trivia bit-———The B17 got the moniker of Flying Fortress in the 1930s when the Army Air Corps was trying to pry funding out of Congress. They sold the program as a defensive extension of the Coast Artillery and not as an offensive weapon for foreign war. Attack an enemy fleet when it was further out to sea.
The name had nothing to do with the plane’s machine guns since the early Forts hardly had any.