Well as for the "Amerika Bomber" as you are all talking about. There was an ongoing project that included the Junker Ju-390, Me-264, and Fw-300.
There are unconfirmed reports that the Ju-390 made a test flight to within sight of the East Coast of the United States. I too dont believe that such a raid would have succeeded with out fighter cover (which was not going to happen). But one thing to think about is the Element of Surprise? Did the United States really think it was going to get hit? They may have thought safe eneogh not to even worry about it. This is all theoretical though and more then likley the easiest way for the Germans to hit New York would have been with rocket firing U-Boots.
Anyway info:
Amerika Bomber
The Amerika Bomber project was an initiative of the German Air Ministry to obtain a long-range bomber aircraft for the Luftwaffe that would be capable of striking the continental United States from Germany. Requests for designs were made to the major German aircraft manufacturers early in World War II, long before the US had entered the war.
The most promising proposals were based on conventional principles of aircraft design and would have yielded aircraft very similar in configuration and capability to the Allied heavy bombers of the day. These included the Messerschmitt Me 264 (an all-new design), the Focke-Wulf Fw 300 (based on the existing Fw 200), and the Junkers Ju 390 (based on the Ju 290). Prototypes of the Me 264 were built, but it was the Ju 390 that was selected for production. Only two prototypes were constructed before the programme was abandoned, although it is widely claimed (and widely disputed) that the second prototype made a trans-Atlantic flight to within 20km (12 miles) of the US coast in early 1944.
Other proposals were far more exotic jet- and rocket-powered designs. Perhaps the best-known of these today is Eugen Sänger's Silbervogel ("Silverbird") sub-orbital bomber. Slightly more conventional, the Horten brothers designed the Horten Ho XVIII, a flying wing powered by six turbojets based on experiences with their existing Ho X design. The Arado company also suggested a six-jet flying wing design, the Arado E.555. All of these projects were deemed too expensive and ambitious and were abandoned, although the British Air Ministry considered development of the Ho XVIII for an airliner after the war, and the theoretical groundwork done on the Silbervogel would prove seminal to lifting body designs of the space age.
http://en.wikipedia.org/wiki/Amerika_Bomber
Messerschmitt Me-264
The Messerschmitt Me 264 Amerika (America) was a long-range strategic bomber aircraft developed during World War II for the Luftwaffe under the Reichsluftfahrtministerium's "Amerika Bomber" programme.
The bomber was to be capable of flying from Germany to New York City and back. One prototype was made but production was abandoned to allow Messerschmitt to concentrate on fighter production and because the Junkers Ju 390 had been selected in its place for the Amerika Bomber.
The Me 264 had four 1,700 hp (1.3 MW) BMW 801G engines and very little armor and guns in the interest of increasing fuel capacity. The heavy bomber would have had a crew of 5-6 and was nearly 21 metres long.
http://en.wikipedia.org/wiki/Messerschmitt_Me_264
Crew:
Length: 20.9 m (68 ft 7 in)
Wingspan: 43.0 m (141 ft)
Height: 4.3 m (14 ft)
Wing area: 127.8 m² (1,376 ft²)
Empty: 21,150 kg (46,620 lb)
Loaded: 23,000 kg (50,000 lb)
Maximum takeoff: 56,000 kg (123,000 lb)
Powerplant: 4× BMW 801G/H, 1,272 kW (1,730 hp) each
Maximum speed: 560 km/h (350 mph)
Range: 14,900 km (9,260 miles)
Service ceiling: 8,000 m (26,000 ft)
Rate of climb: 120 m/min (390 ft/min)
Wing loading: 180 kg/m² (36 lb/ft²)
Power/mass: 0.23 kW/kg (0.14 hp/lb)
4× 13 mm (0.51 in) MG 131 machine guns
2× 20 mm (0.79 in) MG 151 cannon
2,000 kg (4,400 lb) of bombs
Junkers Ju-390
The Junkers Ju 390 was a long-range derivative of the Junkers Ju 290 and was intended to be used as a heavy transport, maritime patrol aircraft, and bomber. It was a design selected for the abortive Amerika Bomber project.
Two prototypes were created by inserting an extra pair of inner wing segments into the wings of basic Ju 290 airframes and adding new sections to "stretch" the fuselages. The resulting giant first flew on October 20, 1943 and performed well, resulting in an order for 26 such aircraft, to be designated Ju 390A-1. None of these were actually built by the time that the project was cancelled (along with Ju 290 production) in mid 1944. The maritime patrol version and bomber were to be designated Ju 390B and Ju 390C respectively. It was suggested that the bomber could have carried the Messerschmitt Me 328 parasite fighter for self-defence. Some test flights are believed to have been performed by Ju-390 aircraft with the anti-shipping Fritz-X guided smart-bomb.
Disputed New York flight in 1944
There is a heavily disputed claim that in January 1944, a Ju-390 prototype made a trans-atlantic flight from Mont-de-Marsan (near Bordeaux) to some 20 km (12 miles) of the coast of the United States and back. Critics claim FAGr.5 (Fernaufsklarungsgruppe 5) never flew such a flight. Supporters say the only link between FAGr.5 and the New York flight is the common use of an airfield at Mont-de-Marsan and the veracity of the New York flight is neither proved nor disproved by a lack of unit records for such a flight. Indeed the flight may have had nothing whatsoever to do with FAGr.5 operations.
Whilst the Ju-390's 32-hour endurance would have certainly made such a crossing theoretically possible, there is a lack of evidence to support the claim. Aviation historian Horst Zoeller claims the flight was recorded in Junkers company records.
Critics have also pointed to the vagueness of the aircraft's alleged position and even the date of what would have been a milestone flight. The best known (and maybe earliest publication) of the claim in English was in William Green's Warplanes of the Third Reich in 1970, where he wrote that the Ju 390 flew to "a point some 12 miles from the US coast, north of New York". Critics say the vagueness of detail and lack of corroborating evidence are hallmarks of an urban legend.
Critics believe that the aircraft would have had to overfly parts of the Massachusetts coast in order to fix their location, and point out the likelihood of the aircraft being spotted by observers and/or radar, which it was not. If New York state were meant, this would have put the aircraft closer to Boston. Critics ask why this city wasn't referred to for fixing the position of the claim. Finally, it is questioned how the aircrew would have been able to fix their position so accurately anyway.
Supporters argue that a Ju-390 crew could have obtained a highly accurate fix from public broadcast radio stations. Also that a Ju-390 would not have needed to overfly Massachusetts at all. They say there was no reason why New York City could not have been approached purely from the sea.
Supporters also note that the mission was designed to deliver a single bomb to New York and that such a bomb could only have been the atomic weapon under development. Japan and Germany at the time were using the "Harteck Process" of gaseous uranium centrifuges. Germany in 1944 was shipping both uranium ores and centrifuges to Japan by U-boat.
Supporters of the New York flight say of course the mission was kept secret so as not to tip off the US Government to provide better air defences. It was an ultra top secret test flight for the delivery of an atomic bomb.
Corroboration is gleened from the so-called Silbervogel sub-orbital bomber designed to attack New York from space with only a single bomb. Only one type of bomb was worth all the time and expense involved. Supporters say a mission so secret would never have found its way into FAGr.5 logbooks.
Supporters note the top secret unit, II/KG200 also flew the Ju-390 as did Junkers company test pilots in Czechoslovakia.
Following the war, Hitler's armaments minister Albert Speer also recounted to author James P O'Donnell that a Ju-390 aircraft flown by Junkers test pilots flew a polar route to Japan in 1944.
http://en.wikipedia.org/wiki/Junkers_Ju_390
Role Transport
Crew 8
First Flight October 20, 1943
Entered Service 1943
Manufacturer Junkers
Length 34.20 m 112 ft 2 in
Wingspan 50.30 m 165 ft 1 in
Height 6.89 m 22 ft 7 in
Wing area 254 m² 2,733 ft²
Empty 39,500 kg 86,900 lb
Loaded 53,112 kg 116,846 lb
Maximum takeoff 75,500 kg 166,100 lb
Engines 6x BMW 801E
Power 8,818 kW 11,820 hp
Maximum speed 505 km/h 314 mph
Range 9,700 km 6,027 miles
Service ceiling 6,000 m 19,680 ft
Rate of climb
Wing loading 209 kg/m² 43 lb/ft²
Power/Mass 0.17 kW/kg 0.10 hp/lb
2x 20 mm MG 151/20 cannons in dorsal turrets
1 x 20 mm MG 151/20 in tail
2x 13 mm MG 131 machine guns at waist
2x 13 mm MG 131 in gondola
