????With the 787 Dreamliner set back again, questions arise for travelers, investors and airlines. Here are some answers.

????By Michael Copeland

????We now know that Boeing's super-cool, and super-late, 787 Dreamliner is going to be earthbound a bit longer. The world's largest commercial aircraft maker announced that during "static" testing they noticed stress where the wings are joined to the body of the plane, a factor that hadn't been predicted in computer models.

????The ground testing is rigorous; this wasn't a case of some beefy guy with a big wrench who stepped on the wing in the wrong place. Engineers found the problem during a phase of safety testing when engineers literally take the wings of the plane and bend them until they practically touch.

????Still, it's not a problem anyone wants when the world's first mostly composite commercial airliner is days away from its critical first flight. This is a plane with a $150 million price tag that is more than two years behind its original schedule and has yet to exhibit the really nifty and useful thing about planes -- flying.

????What this latest delay means to you depends on which part of the Boeing constituency you inhabit: the flying public; an investor; or an airline waiting for its planes. Let's start with those of us who are going to get on this new jet: the flying public.

????The obvious question, is this thing going to be safe? Stress where the wings meet the body, after all, doesn't sound reassuring. Boeing officials were clear in a conference call Tuesday that there is a simple fix for the problem, which requires a handful of reinforcing parts applied to 36 areas on the wings about the size of one or two square inches each. "We have seen nothing about what led us to the discovery that would lead us to broader concerns with the test or flight programs," said Scott Fancher, the 787 vice president and general manager, during the conference call. If the problem had been discovered months ago, Fancher added, rather than days before the plane was supposed to fly, the 787 team would have simply fixed it and moved on, probably without any grand public statement.

????Fancher is not blowing smoke. It is not uncommon for new commercial planes to have issues late in the game, even so close to the first flight. What makes it more painful in this case is that it comes after so many previous delays. Designing and building a new commercial jet is a phenomenally complex process. The Dreamliner even more so. Not only does it use new materials, chiefly composites, but Boeing is also using a new process to get the plane built drawing on suppliers across the world to manufacture parts, which are assembled into the complete airliner at the company's sprawling plant in Everett, Wash.

????Clearly, Boeing doesn't have the process nailed yet, but it is building a safe plane. Not only that, with bigger windows and a climate-control system that more closely approximates sea level, it ought to be more of a pleasure to fly than the aluminum tubes in the sky today.

????If you are an investor you might be a little less sanguine. Boeing (BA, Fortune 500) stock has fallen more than 8% since the delay was announced Tuesday. Still, it has been on a run lately, up almost 50% since its March lows. There are plenty of folks who feel that Boeing stock got ahead of itself, after being beaten down so low earlier in the year.

????How you view the share price depends on whether you are investing for the next six months to a year or longer term, says Alex Hamilton, director of research at Jesup & Lamont, who has a "hold" on the stock. "Financially, first-flight means nothing, it doesn't put another cent in Boeing's pocket," he says. "It was psychological more than anything. What keeps getting Boeing in trouble is setting these bogies [dates] and missing them. They need to keep quiet and just get that plane in the air."

????Missing first-flight does push everything out, however, Hamilton says. "It calls into question whether we can believe they can start to deliver planes in the first quarter of 2010, whether they have the manufacturing process down, and whether they can produce ten aircraft per month as they have planned." As things slip, so might Boeing's earning power in the near-term. If it can't deliver planes, it doesn't get paid, and indeed faces penalties that it must pay customers. Boeing will assess and announce what the financial impact of the delay might be during its second-quarter earnings report next month. In the coming weeks it will also pick a new date for first flight.

????That's the near-term. Longer-term as an investor, you need to consider whether Boeing gets its manufacturing process straight and if the 787 is the breakthrough aircraft Boeing thinks it is. What the 787 offers chiefly is much better fuel efficiency in a package that lowers maintenance costs and opens up new long-distance routes that were simply uneconomic. "Long-term it's a game changer," Hamilton says. "And if you change the game, and you are the market leader, you are in a tremendous position."

????Which brings us to the airlines that are hoping Boeing will help them change the tough economics of their business. Boeing has pre-sold more than 860 of these planes, the fastest pace in history for a new airliner. When the global recession hit, the delay to the 787 wasn't as keenly felt as it otherwise would have been, since the airline industry saw its business plummet. Not taking delivery of expensive planes that they couldn't fill anyway wasn't such a burden. Today, however, airlines are more eager to get delivery, as some see signs of air-travel ticking back up.

????Airlines in India and China are signaling they may be ready to buy new planes, as are some giant commercial-jet leasing companies that have been sitting on the sidelines during the recession. The cost of jet fuel is climbing again, and so having an efficient plane is more desirable than ever.

????First in line for the 787 is All Nippon Airways, which didn't take the news of the delay well. "We are disappointed that the first flight of the 787 will be postponed, and urge Boeing to specify the schedule for the program as a whole as quickly as possible," ANA said in a statement.

????But here's the thing. No matter how disappointed they are, ANA and the dozens of other customers will wait for the 787. Sure it's two-plus years behind, but Boeing's only real competition in the commercial airline business, Airbus, won't have a new plane ready with similar features until 2013 or 2014, and that assumes they don't have their own delays. "If Boeing slips this plane another six to nine months, it might hit their 2010 earnings," says Rick Whittington, a principal with Sarasota, Fla.-based independent aerospace research firm JSA Research. "Investors don't like it, and the customers aren't happy about it, but they are not going to cancel orders because there is nowhere else for them to go."