Question: When was the aircraft manufacturer at which Klapmeier brothers was a co-founder founded? 

Context paragraphs:
Flight Team: Flight Team UG & Company KG (usually just Flight Team) was a German aircraft manufacturer based in Ippesheim, in the district of Neustadt (Aisch)-Bad Windsheim in Bavaria.  As an aircraft manufacturer the company specialized in the design and manufacture of ultralight trikes.

Koolhoven: N.V. Koolhoven was an aircraft manufacturer based in Rotterdam, Netherlands.  From its conception in 1926 to its destruction in the Blitzkrieg in May 1940, the company remained the Dutch second major aircraft manufacturer (after Fokker).  Although many of its aircraft were as unsuccessful economically as they were brilliant from a design standpoint, the company managed to score several 'hits', amongst them the FK-58 single-seat monoplane fighter, the FK-50 twin-engine passenger transport and the FK-41, built in England under licence by Desoutter.

Weller Flugzeugbau: Weller Flugzeugbau (English: Weller Aircraft Construction ) is a German aircraft manufacturer, owned by Roman Weller and based in Biberfeld.  The company was founded in 1987 and in 2012 had two employees.  It specializes in the design and manufacture of ultralight aircraft, aircraft parts and aircraft repairs.  The company has done contract specialized welding for automotive companies, including DaimlerChrysler, Porsche and BMW as well as work for aircraft manufacturers, including Scheibe Flugzeugbau and Sauer aircraft engines, and aviation museums, such as the Musée de l'Air, Deutsches Museum and the Technikmuseum Speyer.

Shenyang Aircraft Corporation: Shenyang Aircraft Corporation or Shenyang Aerospace Corporation () is a Chinese civilian and military aircraft manufacturer located in Shenyang, and is a subsidiary of AVIC.  Founded in 1953, it is one of the oldest aircraft manufacturers in the People's Republic of China.  Many aircraft manufacturers in China such as Chengdu Aircraft Industry Group or Guizhou Aircraft Industry Co. were founded with help from Shenyang.  The company mainly focuses on designing and manufacturing civilian and military aircraft, as well as their related components including jet engines.  It is also involved in the development of UAVs and drones.

Fletcher Aviation: Fletcher Aviation Corporation was an aircraft manufacturer founded by three brothers, Wendell, Frank, Maurice Fletcher, in Pasadena, California in 1941 .  The initial aim of the company was to produce a wooden basic trainer aircraft (the FBT-2) that Wendell had designed, but despite brief interest by the Army in the type to use as a target drone, nothing came of this aircraft.  After relocating to Rosemead, California, later projects involved a family of related designs, including (the FU-24) with 296 produced in New Zealand as an agricultural aircraft with many still operating today.

Curtiss-Wright: The Curtiss-Wright Corporation is an American-based, global diversified product manufacturer and service provider for the commercial, industrial, defense, and energy markets.  Created in 1929 from the consolidation of Curtiss Aeroplane and Motor Company, Wright Aeronautical (founded by Glenn L. Martin and the Wright brothers as Wright-Martin), and various supplier companies, by the end of World War II it was the largest aircraft manufacturer in the United States, supplying whole aircraft in large numbers to the U.S. Armed Forces.  It has since evolved away from final assembly of finished aircraft, becoming a component manufacturer specializing in actuators, aircraft controls, valves, and surface treatment services.  It also is a supplier to commercial nuclear power, nuclear navy systems, industrial vehicles and to the oil and gas industries.

Supplier-furnished equipment: In aviation, when an aircraft is made and delivered it will come with all agreed Supplier-furnished equipment (SFE).  The opposite of SFE is buyer-furnished equipment (BFE), which is purchased by the buyer and given to the aircraft manufacturer to be installed before delivery by the aircraft manufacturer.  BFE includes preferred galley equipment (ovens for example).  In many cases the aircraft is designed to accommodate BFE during the initial engineering phase.

Cirrus Aircraft: The Cirrus Aircraft Corporation (formally Cirrus Design Corporation) is an aircraft manufacturer that was founded in 1984 by Alan and Dale Klapmeier to produce the VK-30 kit aircraft.  The company headquarters is located in Duluth, Minnesota, United States.  As of June 2015, Cirrus had delivered over 6,000 aircraft in 16 years of production, and has been the world's largest producer of piston-powered aircraft since 2013.

Societatea Pentru Exploatări Tehnice: Societatea Pentru Exploatări Technice or SET ("Technical Development Society") was a Romanian aircraft manufacturer.  It was established in Bucharest in 1923 by Grigore Zamfirescu as a general machinery manufacturing plant.  It soon specialised in building aircraft to its founder's design, supplying the Romanian Air Force with trainers during the mid-1930s.  At the peak of aircraft production, Zamfirescu changed the company's name to "Fabrica de Avioane SET".  It was the second biggest Romanian pre-war aircraft manufacturer, after Industria Aeronautică Română (IAR).

Klapmeier brothers: The Klapmeier brothers, Alan Lee Klapmeier (born October 6, 1958) and Dale Edward Klapmeier (born July 2, 1961), are American aircraft designers and aviation entrepreneurs who together founded the Cirrus Aircraft Corporation in 1984.  Under the leadership of the Klapmeiers, Cirrus was the first aircraft manufacturer to install a whole-plane parachute recovery system as a standard on all its models—designed to lower the airplane (and occupants) safely to the ground in case of an emergency.  The device is attributed with saving over 140 lives to date.  Cirrus was also the first to use all-composite airframe construction and glass panel cockpits on production aircraft, which many say revolutionized general aviation for light aircraft pilots.

Supporting paragraphs: Klapmeier brothers Cirrus Aircraft
Answer: 1984