The Commerce Department said Wednesday that orders for durable goods advanced 0.5 percent last month, slightly lower than the 0.7 percent gain that economists had expected.

The increase was led by the second huge jump in demand for commercial aircraft, an increase of 32.7 percent which followed a 134.9 percent rise in this volatile category in January. Excluding transportation, orders posted a 0.9 percent increase, much better than the 0.6 percent decline in January.

The big jump in demand for commercial aircraft was offset by a 1.9 percent drop in demand for motor vehicles, which followed an even bigger 2.3 percent fall in the category in January. Automakers are still struggling to emerge from a steep recession, which has depressed sales and forced General Motors and Chrysler briefly into bankruptcy last year. They emerged with the help of billions of dollars in government support.

Total transportation orders fell by 0.7 percent in February following a 19.4 percent rise in January.

Outside of transportation, orders for machinery rose 4.7 percent, the biggest gain since December, while demand for primary metals such as steel rose 1.5 percent. Demand for computers was up 0.4 percent, but orders for communications equipment fell 1.7 percent.

The 0.5 percent rise in orders in February followed a 3.9 percent increase in January and a gain of 1.8 percent in December. The three straight monthly gains pushed total orders to a seasonally adjusted $178.1 billion in February.

The rebound from the deepest recession since the 1930s has been helped significantly by rising demand for factory goods. American manufacturers are benefiting not only from increased domestic demand, but rising orders from overseas. Overseas orders have been helped by last year's decline in the dollar against many currencies. A weaker dollar makes U.S. products cheaper in foreign markets.

The government will release its final look at overall economic activity in the October-December period on Friday. Economists expect that report to show the gross domestic product growing at an annual rate of 5.9 percent, unchanged from an estimate made a month ago.

About two-thirds of that growth reflected a swing from the massive liquidation of inventories that companies had been undertaking to trim costs during the prolonged recession. Economists are looking for a restocking of inventories to help boost factory production in coming months.