Business Wednesday May 25, 04:28 AM Boeing optimistic on keeping 747, 767 production lines NEW YORK (Reuters) - Boeing Co. is optimistic that it will get enough orders for its aging 767 and 747 jets to continue production past this year, the chief executive of its commercial aircraft unit said on Tuesday. "We're very pleasantly surprised," Alan Mulally said when asked at a company conference for analysts and investors about ongoing demand for the two aircraft which are both expected to be replaced by newer models in coming years. Boeing is marketing the so-called 747 Advanced as a successor plane...