Richard Santulli, the man credited with starting the fractional aircraft industry, has abruptly resigned as chairman and chief executive of NetJets, the world's largest fractional aircraft provider.Santulli founded NetJets in 1986 after purchasing Ohio-based Executive Jet Aviation and built the company into an international powerhouse with more than 800 aircraft.The company was bought by billionaire investor Warren Buffet's Berkshire Hathaway organisation in 1998 for $725 million. Buffet was a customer before he became the owner. Succeeding Santulli as chairman and interim chief executive is David Sokol, chairman at Berkshire's MidAmerican Energy Holdings and a man rumoured to be in line to take Buffet's position when he retires.Santulli says he will spend "more time with my young family and pursue other interests". Source : Netjets Europe