In his annual letter to Berkshire Hathaway shareholders, investment mogul Warren Buffett said the company's flight-services division-which includes fractional provider NetJets and aviation training company FlightSafety International-set a record last year with pre-tax earnings increasing 49 percent to $547 million. "Corporate aviation had an extraordinary year worldwide, and both of our companies-as runaway leaders in their fields-fully participated," he wrote. NetJets, which Buffett regards as the "unchallenged leader" in the fractional industry, currently operates 487 jets in the U.S. and 135 in Europe. Though NetJets Europe ran cumulative losses of $212 million in its first 10 years of operation, it now has "real momentum," he said, with earnings tripling there last year. The U.S. operation is also doing well financially, he wrote. At FlightSafety, revenues climbed 14 percent and pre-tax earnings soared 20 percent.