United Launch Alliance, a joint venture of Lockheed Martin Corp (LMT.N) and Boeing Co (BA.N), on Friday said it was cutting its executive ranks by 30 percent in December through what it called voluntary departures by 12 executives. Tory Bruno, chief executive of the venture, told Reuters in an emailed statement the layoffs were part of ULA’s ongoing efforts to adapt to what he called “an increasingly competitive business environment” and redesign its leadership team. ULA, formed by the two largest U.S. weapons makers in 2006, has long been the sole company able to launch U.S.