5a, whilst in the field of ordnance he created the Hispano-Suiza HS.404 20mm autocannon, which was of great importance in WW II as the main fighter gun of the RAF from 1941 onwards.

He then designed and manufactured two models of gasoline powered carts: a 4.5 hp single-cylinder and the 7.5-horsepower twin-cylinder La Cuadra Centauro, which in 1901 traveled 1,000 km without incident.

The Spanish businessmen Damian Mateù and Francisco Seix then finance on June 14, 1904, the new company Hispano-Suiza Fabrica de Automóviles SA in Barcelona.

A new factory was built in Sagrera and sales offices were created in Geneva and Paris, then in the rest of Europe[citation needed].

A sales license was granted to the Swiss company SAG (Société d'automobiles à Genève) of Lucien Pictet and Paul Piccard.

From 1915 the French air force successfully equipped itself with 40,000 of these engines, which enabled them to fight on equal terms with their German counterparts.

Marc Birkigt stopped manufacturing automobiles and devoted himself to aircraft engines and automatic weapons for French national defense.

The Hispano-Suiza HS-404 aircraft gun was also designed and widely adopted by the British and American armed forces during World War II.

It then relaunched in the manufacture of aircraft reactors (Rolls-Royce), aviation accessories (thrust reversers, gas turbines, landing gear, diesel engines ...) Marc Birkigt married Eugénie Brachet in Geneva on November 23, 1901.