German airline Lufthansa plans to cooperate on private jets with NetJets Inc, the corporate aircraft unit of Warren Buffet's Berkshire Hathaway Inc (BRKa.N), according to a German magazine.The two airlines will enter into a joint venture under the name "Lufthansa Private Jet", magazine Wirtschaftswoche said on Monday, citing a person familiar with the matter.Netjets will fly all passengers who book a corporate jet seat with Lufthansa, which can cost up to 20,000 euros, according to the magazine.The service, which offers individually bookable private jets on demand, is currently run by a subsidiary of Lufthansa.Lufthansa has used Netjets for its private jet operation in the past but their cooperation between 2005 and 2007 ended because Netjets wanted to poach Lufthansa's wealthy customers, Wirtschaftswoche quoted industry sources as saying.Lufthansa then commissioned its subsidiary Swiss Private Aviation to run the service, but closed the unit at the end of 2010 because it was not profitable, according to the magazine.Lufthansa and Netjets both declined to comment. (Reporting by Michelle Martin; Editing by Greg Mahlich)