Stratolaunch, the world's largest airplane that flew only once, is up for sale. Holding company Vulcan is seeking to sell Stratolaunch at $400 million, people familiar with the matter told CNBC. Vulcan is the investment conglomerate of the late billionaire Paul Allen. A Microsoft co-founder, Allen passed away last October following complications of non-Hodgkin's lymphoma. Vulcan and Stratolaunch did not respond to multiple CNBC requests for comment. The hefty price tag includes… (www.msn.com) 更多...