Orders to U.S. factories increased in July by the largest amount in nine months, propelled by a big jump in demand for commercial aircraft. The key category that tracks business investment plans posted the best increase since January.

The Commerce Department says factory orders rose 1.9 percent in July. It was the biggest one-month gain since last October and was led by a surge in orders in the volatile category of commercial aircraft. Orders in the category that serves as a proxy for business investment increased 1.5 percent, the best showing since January.

Economists are hoping that after a period of weakness, business investment will begin to rebound in the second half of this year. Supporting that view, demand for oil field equipment rose for a third month.