Hooray, it's earning season! Fellow stock-investing buffs rejoice! Quarterly earnings can be either encouraging or painful, but investors need to keep in mind that in the grand scheme of things, a three-month period is a really tiny window by to judge a company's operations. Today's third-quarter releases were encouraging for Boeing (NYSE:BA) and painful for Caterpillar (NYSE:CAT), which are today's biggest winner and loser, respectively, in the Dow Jones Industrial Average (DJINDICES:^DJI).

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Winner, winner
Despite battery problems and grounded 787 airplanes, Boeing's stock has been flying high this year. Boeing's the biggest winner in the Dow today by a long shot, and its stock has jumped more than 5% since its quarterly report hit the news feeds.

Boeing's stock price doesn't look set to crash anytime soon after the company posted a strong third quarter and raised guidance for the year. Let's dig into some of the highlights, starting from the top. Boeing's revenue jumped 11% compared to last year's third quarter. Boeing's overall operating margin bounced 30 basis points higher to 8.1%, led by stronger margins in its commercial aircraft segment. That will be an important factor for investors to watch going forward, because Boeing will see margin pressure as it ramps up production on its 787 Dreamliner -- a less efficient operation, currently.

It's improved margins in the quarter helped drive net earnings 12% higher year over year and brought earnings per share to $1.51. That handily beat estimates, and management raised its EPS guidance to between $6.50 and $6.65 for the year.

"Consistently strong operating performance is driving higher earnings, revenue and cash flow as we deliver on our record backlog and return increased value to shareholders," Boeing Chairman, President and CEO Jim McNerney said in a press release.

Biggest loser
Unfortunately for Caterpillar, the world's largest seller of bulldozers and excavators, continues to only dig itself a deeper hole. Its earnings were the opposite of Boeing's, and its stock is trading 6% lower at the bottom of the Dow Jones Industrial Average.

There aren't a lot of positives in Caterpillar's report, and global demand for mining equipment continues to look bleak. Caterpillar's third-quarter earnings plunged 44%, and management lowered its full year guidance to $5.50 per share, from $6.50. Its revenue declined 18% to $13 billion, and the pain looks to continue as management expects sales to be flat in 2014, give or take 5%.

"Unfortunately, order rates have not picked up much despite continuing strong commodity production," said chairman and chief executive Doug Oberhelman, according to Morningstar. "That has caused us to ratchet down our sales and revenues outlook as we have moved through 2013."

Fool contributor Daniel Miller has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.