The Luftwaffe began planning for possible trans-Atlantic strategic bombing missions early in World War II, with Albert Speer stating in his own post-war book, Spandau: The Secret Diaries, that Adolf Hitler was fascinated with the idea of New York City in flames.
The feasibility of an attack on the continental United States by Imperial Japan was considered negligible, with Japan possessing neither the manpower nor logistical ability to successfully mount a full-scale invasion of the U.S [REF].