The numbers: Orders for American-made durable goods sank in October, but it was mostly due to a dropoff in demand for airplanes of all types. More notably, business investment was weak for the third month in a row.

Orders fell 4.4% to mark the biggest decline in 15 months, the government said Wednesday. Economists surveyed by MarketWatch had forecast a 3.4% decline in orders for durable goods, or products made to last at least three years.

Bookings for commercial jets slid 21.4% and they shrank 59% for fighter jets and other military aircraft.

Stripping out planes and cars, orders rose a slight 0.1%. Transportation often exaggerates the ups and downs in orders because of lumpy demand from one month to the next.

What happened: The pullback in aircraft orders was not surprising. Boeing BA, -3.39% tends to receive fewer orders late in the year after a summer bonanza. Orders for defense aircraft, what’s more, posted the biggest monthly increase in September in 17 years. So a reversal was expected.

Aside from aircraft, orders also declined for machinery and primary metals.

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Orders rose for computers, networking gear and electrical equipment.

The biggest takeaway from the October report was another soft reading on business investment. So-called core orders fell slightly last month following small declines in September and August.

Although the closely followed measure has risen 3.2% in the past 12 months, it was increasing at a 8% pace earlier in the year.

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Big picture: Business investment has cooled off in the fall, adding to fresh worries about the economy. Stronger corporate spending has buoyed the economy over the past year and a half.

Some economists contend the slowdown is likely to be temporary. They say companies need to invest more in equipment and automation to counter rising wages and a growing shortage of skilled workers.

Yet others suggest that businesses might be more hesitant because of a slowing global economy and rising trade tensions with China that appear to have no easy resolution.

Read:Global growth will slow from here

What they are saying?: “Looking ahead, we expect momentum to continue to fade as reduced tailwinds from fiscal stimulus dissipate and rising headwinds from slower global growth, reduced energy investment and heightened trade tensions start weighing on capex plans,” economists at Oxford Economics said.

Market reaction: The Dow Jones Industrial Average DJIA, +0.19% and the S&P 500 SPX, +0.29% rose in Wednesday trades after a pair of brutal selloffs this week erased all stock-market gains for 2018. Yet a mediocre durable-goods report, an increase in jobless claims and a softer sentiment survey could limit the gains.