Warren Buffett's investment vehicle Berkshire Hathaway Inc. said Tuesday it is buying a 38.6% stake in Pilot Travel Centers LLC, which does business as Pilot Flying J, a family-owned operator of travel centers in North America. The Haslam family will continue to own a majority stake in the company, which has more than $20 billion in revenues, more than 27,000 employees and 750 locations across the U.S. and Canada, Berkshire said in a statement. Jimmy Haslam will remain as chief executive, and the management team will remain in place. The company will remain headquartered in Knoxville, TN.