An additional United States intelligence report shows that the Japanese were developing technology that was much more explicitly stealth than what was applied to the Horton Ho 229.

The Horten Ho 229 is known by several different names. The Horten Brothers called the plane the H.IX, so it is often called the Horten H.IX. Reichsluftfahrtministerium, the German Ministry of Aviation, gave the plane the identity Ho 229. At times it is referred to as the Gotha Go 229, due to the German manufacturer chosen to produce the plane, Gothaer Waggonfabrik. According to William Green, author of "Warplanes of the Third Reich," the Ho 229 was the first "flying wing" aircraft with a jet engine. It was the the first plane with design elements, which can be referred to as stealth technology, to hinder the effectiveness of radar to detect the plane.

In 1943, the head of the German Luftwaffe, Reichsmarschall Hermann Göring, presented to the German aircraft industry what is known as the "3 X 1000" goal. Goring wanted a plane that could carry 1000 kg of bombs (2,200 lb), with a range of 1000 km (620 miles), at a speed of 1000 km/h (620 mph). The Horten Brothers had been working on flying wing design gliders since the early 1930's. They believed that the low-drag of the gliders they made in the past could be the basis for a craft that would meet Goring's demands. The H.IX's wings were made from two carbon injected plywood panels adhered to each other with a charcoal and sawdust mixture.

In 1943, Göring awarded 500,000 Reich Marks to the Horten Brothers to build and fly several prototypes of the all-wing and jet-propelled Horten H IX. The Hortens test flew an unpowered glider, the prototype H.IX V1 in March of 1944. The aircraft did not look like any existing plane in use during World War II. It looked very similar to the modern American B-2 Bomber. Goering was impressed with the design and transferred it away from the Hortens to the German aerospace company Gothaer Waggonfabrik.

At Gothaer the design went through several major improvements. The result was a jet powered prototype, the H.IX V2, which was first flown on February 2^nd, 1945.

Removed from the project, the Horten Brothers were working on the Horten H.XVIII, also called the Amerika Bomber. The Horten H.XVIII was an attempt to fulfill the German desire to build a bomber that could reach the United States. After several more test flights, the Ho 229 was added to the German Jäger-Notprogramm, or Emergency Fighter Program on March 12, 1945.

Work on the next prototype version of the plane, the H.IX V3, ended when the American 3rd Army's VII Corps on April 14, 1945 reached the Gotha plant in Friederichsroda.

In 2008, Northrop-Grumman using available design plans built a full-size reproduction of the H.IX V3 using materials available in Germany in 1945. They also studied the only surviving parts of a Ho 229 V3, which were housed at the Smithsonian National Air and Space Museum's Paul E. Garber Restoration and Storage Facility just outside of Washington DC in Suitland, Maryland.

Engineers at Northrop wanted to find out if the German craft could actually be radar resistant. Northrop tested the non-flying reproduction at its classified radar testing facility in Tejon, California. During the testing the frequencies used by British radar facilities at the end of the war were directed at the reproduction. Tom Dobrenz, a Northrop Grumman stealth expert said about the H.IX, "This design gave them just about a 20 percent reduction in radar range detection over a conventional fighter of the day."

When combined with the speed of the H.IX, after detection by British homeland defense radar, the Royal Air Force would have had 8 minutes from the time of spotting the aircraft before it reached England, instead of the usual 19 minutes.

While the design was proven to be stealthy, it has been argued that it was not designed to stealthy. There is no documented evidence in Germany that the design was intended to be what would later be called stealth.

In an article written by Reimar Horten published in the May 1950 edition of the Argentine aerospace magazine Revista Nacional de Aeronautica, Reimar wrote, "...with the advent of radar, wood constructions already considered antique, turned into something modern again. As reflection of electric waves on metallic surfaces is good, such will be the image on the radar screen; on the contrary, on wood surfaces, that reflection is little, these resulting barely visible on the radar."

In the late 1970s and early 1980s, information began to leak to the media that the United States was working on aircraft with stealth technology.

In 1983, Reimar Horten wrote in Nurflugel: Die Geschichte der Horten-Flugzeuge 1933-1960 (Herbert Weishaupt, 1983) that he had planned to combine a mixture of sawdust, charcoal, and glue between the layers of wood that formed large areas of the exterior surface of the H IX wing to shield, he said, the "whole airplane" from radar, because "the charcoal should absorb the electrical waves. Under this shield, then also the tubular steel [airframe] and the engines [would be] "invisible" [to radar]" (p. 136, author translation).

By 1983, the basic elements of American stealth technology were already public knowledge.