Driven by a surge in orders for airplanes, orders for U.S.-made factory goods increased 2.9% in May, the Commerce Department estimated Tuesday. Economists were looking for a gain of about 2.8% in factory orders, according to a survey conducted by MarketWatch. It was the biggest gain in factory orders in 14 months. Factory orders had increased 0.7% in March and April after small declines in January and February. Orders are up 7.1% in the past 12 months. Excluding the surge in civilian and defense aircraft orders, however, orders for factory goods fell 0.3% in May. Shipments of factory goods were flat in May after a 0.7% gain in April. Shipments are up 7.5% in the past year. Inventories increased 0.3% in May, while unfilled orders rose 1.9%. As in the preliminary report, orders for durable goods, such as airplanes, computers, and washing machines, increased 5.5% in May. Demand was weak outside the transportation sector, with orders for machinery falling 2.6% Orders for core capital goods (excluding aircraft and defense goods) fell 2.5% in May after a 1.7% gain in April. Core capital goods orders are up 10.5% in the past year, indicating robust demand for investment goods. Shipments of durable goods fell 0.2% in May, while shipments of core capital goods increased 0.5%.