CHICAGO — Boeing's ambitions seem to have outflown its abilities, as the company's plans to reinvent the way jetliners are built keep faltering, forcing it to post a big loss in the third quarter.

The airplane maker has struggled to get its 787 passenger plane and a revamped version of the 747 jumbo jet off the ground. Delays, parts shortages and last-minute fixes have cost it billions in extra expenses and lost years. That's on top of weak demand for aircraft as air travel and freight shipments take a hit during the economic downturn.

But Boeing's troubles have arisen partly from a new approach to plane building. In recent years, the company has outsourced manufacturing and engineering work to suppliers around the world. It's also started using carbon composite parts to reduce weight and improve fuel efficiency.

Those technological leaps have proved popular in the marketplace — the 787 has more orders than any other new plane — but troublesome for the Chicago-based company.

"We experienced a bridge too far, leading-edge kind of development, which is what we are trying to recover from right now," Boeing chief executive Jim McNerney said in a conference call following the company's earnings announcement.

During the quarter, Boeing's sales edged up 9 percent, but charges of more than $3.6 billion for the 787 and 747-8 programs resulted in a loss of $1.56 billion, or $2.23 per share. It was a disappointing shift from a year earlier, when the company earned $695 million, or 96 cents per share.

The charges also led Boeing to cut its 2009 profit forecast to $1.35 to $1.55 per share from $4.70 to $5 per share.

Matt Collins, an analyst at Edward Jones, said he wasn't surprised by Boeing's results.

"Right now, there's not much they can say to regain investor confidence," he said. "They just need to execute. The third quarter is almost a non-issue. It's what's going to happen with the 787 and 747-8."

Both the new 747 and 787 have had their original test flights and deliveries to customers pushed back by years. That's partly because suppliers have botched certain work, such as the installation of fasteners that hold the plane together.