Japan built many interesting aircraft in WWII – the fastest of which was the Nakajima Ki-84 Hayate ‘Frank’, however, none of these attacked the US Mainland. History is full of many bizarre tales – and one of them is the only time the Lower 48 came under air attack in WWII was from (oddly) a submarine. On September 9, 1942, the mountains of Oregon near Brookings were air raided by a lonely Japanese floatplane .