Germany's WWII plan to bomb US cities through Amerikabomber initiative

Four main candidates were considered for the Amerikabomber: Messerschmitt Me 264, Focke-Wulf Ta 400, Junkers Ju 390, and Heinkel He 277. Of these, three Messerschmitt Me 264 prototypes were constructed along with parts for a Heinkel He 277 and an incomplete Focke-Wulf Ta-400.

The ranges and capabilities of these bombers varied significantly. For example, the Junkers Ju 290 had a range of approximately 4,970 miles with a combat load while other models like the B-29 Superfortress had different specifications.

Japan also pursued similar ambitions with its own long-range bomber projects such as Nakajima G10N Fugaku under Project Z. However, Japan faced even greater resource constraints than Germany and eventually abandoned these plans to focus on defending its home islands.

In addition to conventional bomber designs, Germany explored innovative concepts like "Projekt A," which involved using large aircraft to carry smaller bombers across the Atlantic Ocean before releasing them over targets on America's East Coast. One version called Huckepack Projekt proposed using a Heinkel He 177 bomber to transport a Dornier Do 217 medium/heavy bomber equipped with an additional ramjet engine for extended range missions.

Despite various efforts by both Axis powers during WWII towards developing long-range bombing capabilities against America through their respective programs - none ultimately materialized into successful operations due largely due logistical challenges coupled with shifting priorities amidst ongoing conflicts elsewhere globally at that time period