Jaray, of Hungarian-Jewish descent, was born in Vienna. Jaray studied at Maschinenbauschule in Vienna and worked at the Prague Technical University as an assistant to Professor Rudolf Dörfl. Later he became the chief design engineer for the aircraft building firm Flugzeugbau in Friedrichshafen designing seaplanes. From 1915 Jaray worked at Luftschiffbau Zeppelin located in the same town concentrating on streamlining airships. Jaray designed airship LZ-120Bodensee on which airships such as LZ 127 Graf Zeppelin, LZ 129 Hindenburg and LZ-130 were later based. Further experiments in the LZ’s wind tunnel led to his establishment of streamlining principles for car designs. In 1923 he moved permanently to Switzerland opening an office in Brunnen. In 1927, Jaray founded the Stromlinien Karosserie Gesellschaft, which presented numerous designs for streamlined car body work. It issued licences to major vehicle manufacturers including Tatra Works in Kopřivnice, Czechoslovakia. Tatra was the only manufacturer that introduced Jaray streamlining principles into their car production. Jaray designed his own cars starting with the 1923 Ley and followed on with designs for Chrysler, Mercedes-Benz, Maybach, Apollo, Dixi, Audi, Adler, Jawa, Ford, Steyer and others. His own 1933 car was built on Mercedes-Benz chassis with the body by Huber and Bruehwiler of Lucerne. Jaray was also interested in radio and television technology. In 1941 he worked for Farner AG in Grenchen on nosewheel undercarriage design. In 1944 he set up as an independent engineer working on wind-driven power station. He was an author of a large number of technical patents relating to streamlining, air compressors for railway, and devices for handling gases in silencers. Later he lectured at Eidgenoessische Technische Hochschule (Swiss Federal Institute of Technology), Zurich.