As we close out the trading week, aircraft-manufacturing superstar Boeing (NYSE:BA) has seen its stock fall 4.5% in the wake of a mixed bag of earnings news. Profits for the quarter came in at a healthy $0.89 per share, even after the firm's hefty $0.22-per-share charge to exit its "Connexion by Boeing" broadband business. Sales, in contrast, came in at "only" $14.7 billion. The former was ahead of expectations; the latter, about 3% short.

Free cash flow year to date has already hit the $4 billion mark -- that's up 14% from the $3.5 billion worth of cash profits Boeing had netted by this time last year. What's more, if not for the firm's $615 million settlement with the Department of Justice (a one-time event), free cash flow would have increased 31%.

What's the best thing about Boeing, though, from a blue-chip investor's perspective? I'd have to say it's the company's current $229 billion worth of backlogged business. The bigger a firm's backlog, the more confidence an investor can have in its future.

In Boeing's case, for example, these $229 billion worth of not-yet-built, not-yet-delivered, but known-in-advance sales can keep it in business even if it sells not one single new plane for the next four years. It can also give an investor more than the usual level of confidence in a firm's forward guidance (management, by the way, upped its own earnings guidance by $0.20, to about $4.55 per share, on at least $65.5 billion in 2007 sales). With the sales already in place, all the company has to do now is build and deliver the product.

Back to the future
On a completely different matter, I want to revisit an observation I made in last week's Foolish Forecast regarding Boeing's research and development spending. As you may recall, I pointed out that in the first half of 2006, the firm spent 37% more on R&D than it did in the first half of 2005. I argued then that this was a good thing -- it meant that Boeing was taking full advantage of Airbus' recent troubles by spending to develop new planes while Airbus was busy trying to fix problems on its current model. Turns out that may only be partly true.

Hidden deep within a press release, the following tidbit added some context to Boeing's surge in R&D spending: "The 787 program continues to experience pressures with respect to weight and supplier implementation. The company is raising its R&D forecast to reflect these increasing pressures." It didn't say exactly how much of the $3.1 billion to $3.2 billion it expects to spend on R&D this year is aimed at fixing the 787's problems. But this comment at least tells us that not all of Boeing's R&D cash is being used to whap Airbus over the head while it's down -- and that the firm needs at least some of that money to fix its own mistakes.

Don't stop there. Find out how Boeing's defense-contracting peers did last quarter. We've covered:

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Fool contributor Rich Smith does not own shares of any company named above. The Fool has a disclosure policy.