By MARTIN CRUTSINGERWASHINGTON (AP) â¿¿ Orders to U.S. factories fell in March by the largest amount in seven months, but a key category that signals business investment plans increased. Factory orders dropped 4 percent in March, reflecting a big plunge in the volatile category of commercial aircraft, the Commerce Department reported Friday. Orders had been up 1.9 percent in February. Orders in a category considered a proxy for business investment plans rose 0.9 percent, a modest gain but an improvement from a preliminary report last week that had shown a decline. Weaker economies overseas and the impact of across-the-board government spending cuts have made businesses more cautious, dampening demand for manufactured goods. But even with the March decline, total orders stood at $467.3 billion, 43 percent above the recession low hit in March 2009. Demand for durable goods, items expected to last at least three years, fell 5.8 percent in March, after a 4.3 percent February increase. Orders for nondurable goods, items such as chemicals, petroleum and paper, were down 2.4 percent following a 0.1 percent dip in February. This weakness partly reflects falling prices for energy products. The 0.9 percent rise in core capital goods, the category watched for business investment, followed a 4.8 percent decline in February and a 6.7 percent surge in January. In the durable goods area, orders for commercial aircraft plunged 48.3 percent. And demand for autos and auto parts fell 0.4 percent, although the drop is expected to be reversed in coming months given recent strong auto sales. Orders for machinery dipped 0.8 percent. Demand for primary metals such as steel fell 3.2 percent. Orders for computers rose 2.9 percent. Orders for electric turbines and communications equipment also showed strength. A separate report Friday showed U.S. employers added 165,000 jobs in April, helping to push the unemployment rate down to a four-year low of 7.5 percent. Economists were also encouraged because Friday's report revised the past two months to show hiring was much stronger than previously thought.