In Wild Wild West, when Jim and Artimus are flying on their contraption towards the giant spider-machine, they begin to be shot at by flak guns. If the airplane, or any aircraft for that matter, were not invented at that point, why would the machine have flak guns, anti-aircraft devices?
Don't they just point the gatling guns already mounted on the Tarantula upwards? It's kinda unlikely they'd be built to point upwards, but I suppose someone could knock a restraining block out or something. The question then is why would you build a gatling gun to swivel upwards when you're already on a mounted platform 30-40+ feet above the ground? :)