Boeing Co. announced the third major delay in six months of its 787 Dreamliner on Wednesday, blaming it on assembly delays and further supply problems, and said delivery is now almost 15 months behind schedule.

The world's second-largest maker of commercial jets said the new aircraft will pushed into the fourth quarter of this year instead of the second quarter, and first delivery is expected in the third quarter of 2009 instead of first quarter.

Further delays of the Dreamliner, a fuel-efficient aircraft, narrows Boeing's advantage over rival Airbus who is set to release its SAS's A350 jetliner in 2013.

Boeing shares rose 3.6 percent in morning market trading to $77.69, up from a close at $75.02 on the New York Stock Exchange on Tuesday. The stock has tumbled 30 percent since last summer on worries about the 787.

The new production schedule includes additional schedule margin to reduce risk of further delays on the program, Boeing said in a statement.

Boeing said significant progress has been made in assembling the first airplane but that the first flight is being rescheduled due to slower than expected completion of work that traveled from supplier facilities into Boeing's final assembly line, unanticipated rework, and the addition of margin into the testing schedule.

Over the past few months, we have taken strong actions to confront and overcome start-up issues on the program, and we have made solid progress, said Boeing Commercial Airplanes president and chief executive Scott Carson.

Nevertheless, the traveled work situation and some unanticipated rework have prevented us from hitting the milestones we laid out in January. Our revised schedule is built upon an achievable, high-confidence plan for getting us to our power-on and first-flight milestones.

The Dreamliner, Boeing's first new model in over a decade, is designed using high-tech plastic composites instead of aluminum.

The aerospace giant plans to build around 2,000 Dreamliner's over the next two decades, and boasts the new aircraft consumes 20 percent less fuel compared to planes of a similar size.

The plane is also lighter since almost 50 percent of its primary structure, including its central body and wings, are made of composites such as carbon-fiber. The highly touted aircraft will have the capacity to fly 9,700 miles (15,750 kilometers) without refueling.