By 1944, the perfected war model, the Haunebu II Do-Stra (Dornier STRAtospharen Flugzeug/Stratospheric Aircraft) was tested. Two prototypes were built. These massive machines were crewed by 9 men but with room for up to 20 men. They were also capable of hypersonic speed beyond 21,000 km/h (13,049 mph). The SS had intended to produce the machines and received tenders for both Junkers and Dornier but in late 1944/early 1945 Dornier was chosen. However, due to the end of the war, Dornier were prevented from building any production models.
Larger still was the 71 metre diameter Haunebu III. A lone prototype was built before the end of the war. It was crewed by 32 and could achieve speeds of 7,000 to 40,000 km/h (4350 to 24,855 mph). It had a triple layered Victalen hull. It is said to have had a flight endurance of 7 to 8 weeks and that it made a total of 19 test flights. This craft was to be used for evacuation work for Thule and Vril in March of 1945.
It is believed that the Nazis had further plans for a whopping 120 metre diameter Haunebu IV. Although no such craft is known to have been built before the end of the war.