Although stealth dates back to WW1 with German white doped linen Taubes invisible at 1200 ft and cellon experiments with Fokker fighters and the Linke-Hoffman R.I bomber... the real stealth studies came in WW2 and were applied by the Kriegsmarine first with stealth coatings of Opanol and Tarnmatte for the Type XXI U-boat to defeat sonar and also to shield the schnorkel from radar. The Luftwaffe then began to study stealth for their aircraft and the Ho-IX was used. It was a flying wing of wooden construction that was filled with a sawdust and charcoal filler in a resin matrix to absorb radar. Anti-radar paints were being developed to coat the leading edges of the wings along with other dielectric materials to trap radar waves or disperse them. The Ho-IX was tested at Gottingen and not picked up by radar. The US took the Ho-IX V3 back to the US for study and developed some early types of stealth paint (Ironball) as well as anti-radar grooves for aircraft fuselages, but nothing major was required unti the 1970s when the USAF tested RAM on a Windecker Eagle first and then through Intel on a Soviet book that was declassified the Lockheed "Hopeless Diamond" was projected. This involved faceting which led to the Have Blue program and then the F-117. The West Germans by 1981 had independently also come up with a stealth interceptor, the MBB Lampyridae which infuriated the USAF when they visited MBB and saw it. W Germany was pressured to drop their program but retianed the knowledge after 1989 and designed a range of stealth craft that MAY have led to sightings in 1990 at the Overberg Test Range in the RSA of two German stealth triangles- blackcraft...

Ho-IX V2: http://www.century-of-flight.net/Aviation%20history/flying%20wings/images4/6.jpg In flight: http://www.nurflugel.com/Nurflugel/Horten_Nurflugels/ho_ix/ho_ix_first_flight.jpg MBB Lampyridae: http://rareaircraf1.greyfalcon.us/picturesg/la1.jpg