New orders to U.S. factories fell for a second consecutive month in September, dragged lower by declining demand in the volatile aircraft category, the government reported Tuesday, indicating a temporary setback for the manufacturing sector. The Commerce Department said orders fell 0.6 percent—in line with analyst expectations—after plunging 10 percent in August. Orders declined in September for aircraft, machinery, capital goods, and computers and electronics. Orders for metals, furniture, and motor vehicles rose. There are often dramatic monthly swings in demand for aircraft, which before dropping in September and August had soared by 315 percent in July. Excluding the volatile transportation sector, factory orders have been flat for two consecutive months. Despite the decrease in September orders, there were signs of underlying strength. Unfilled orders at factories rose 0.3 percent after increasing 0.6 percent in August. Order backlogs have increased in 17 of the last 18 months. And shipments rebounded slightly after falling in August, while inventories rose slightly.