A gauge of business investment plans was unexpectedly flat in November, suggesting a slowdown in economic growth after a brisk expansion over the last two quarters.

The Commerce Department said on Tuesday non-defense capital goods orders excluding aircraft, a closely watched proxy for business spending plans, was unchanged after a downwardly revised 1.9 percent drop in October.

The weakness in the so-called core capital goods orders is at odds with retail sales, industrial production and employment data that have indicated a strong undertone in the economy.

Economists polled by Reuters had forecast core capital goods orders increasing 1.5 percent last month after a previously reported 1.6 percent decline in October.

Shipments of core capital goods, which are used to calculate equipment spending in the government's gross domestic product measurement, rose 0.2 percent last month after slipping 0.9 percent in October.

Overall orders for durable goods — items ranging from toasters to aircraft that are meant to last three years or more — unexpectedly fell 0.7 percent, even as Boeing reported a surge in aircraft orders last month.

Durable goods orders have been volatile in recent months because of big swings in aircraft orders. They rose 0.3 percent in October. Orders for transportation equipment fell 1.2 percent last month after increasing 3.3 percent in October.

Boeing received 224 aircraft orders in November, sharply up from only 46 in October, according to information posted on the planemaker's website.

Automobile orders rose only 0.2 percent last month. There were declines in orders for primary metals and computers and electronic products. Orders for machinery rose, while those for electrical equipment, appliances and components were flat.