Boeing had initially planned to mount a first flight of the Dreamliner, seen as the future profit driver for the company, in late September.

Boeing executives said in a conference call that more time was needed to finish the Dreamliner's assembly and get key onboard computer equipment up and running. The first test flights were now set for between mid-November and mid-December.

The 787, unveiled on July 8 at Boeing's plant in Everett, Washington, is the company's first new commercial airliner in 13 years.

Scott Carson, chief executive of the Boeing Commercial Airplanes unit, said the US aerospace giant still expected to maintain its first deliveries on schedule.

"Delivery is without question an important milestone and we'll deliver our first plane in May 2008," Carson said.

Mike Bair, Boeing vice president and general manager for the 787 program, said the company was completing required software for the plane and also taking more time to integrate the various components made around the world.

"We won't fly the 787 until it's ready," Bair said, adding that the company would provide an update in late October on plans for the test flight.

The Dreamliner takes advantage of the advances made in aviation technology in the past decade, including the use of high-tech composites instead of aluminium.

Up to 50 per cent of the primary structure of the plane – including the fuselage and wing – are made of composites such as carbon-fibre, which reduce the weight of the planes and thus save fuel.

The promise of lower fuel costs at a time of rising oil prices in a sector where profit margins are already razor-thin has whetted the appetites of several key players in the airline industry.

The Dreamliner's production is more complex than most other planes, because its components are made in a variety of locations around the world.

Boeing, which aims to build 2,000 Dreamliners over the next two decades, has so far received 706 orders from 48 customers for the plane, which has a catalogue price of between $177 and $243 million.

The latest order was announced recently by Boeing and Russian flagship carrier Aeroflot for 22 Boeing 787-8s, and is worth some $4.4 billion at list prices.

The Dreamliner is expected to help Boeing in its competition against European maker Airbus, which has taken a different strategy by introducing a superjumbo plane, the A380.

Smaller than a jumbo jet, the Dreamliner is able to fly up to 15,750km without refuelling, easily managing a flight between New York and Manila, or Moscow and Sao Paulo, routes so far only open to bigger planes such as Boeing's 777 or 747.

Boeing hopes the Dreamliner will be used to open up profitable flights between cities which so far have no direct links such as Seattle-Shanghai, Boston-Athens or Madrid-Manila.

The Dreamliner's other innovations include greater levels of comfort for passengers, with bigger windows, higher humidity levels within the cabin expected to reduce passenger dehydration and a new anti-turbulence system.

The 787 will go into service after Airbus's mammoth A380 takes to the skies. The first units of the double-decker superjumbo – capable of seating up to 800 passengers – will be delivered to Singapore Airlines in October.

Analysts say the Dreamliner and the A380 reflect the different strategies of Boeing and Airbus as they seek to achieve the same objective – cheaper air travel.

The Airbus A350, seen as a more direct competitor with the 787, has been delayed and is now expected to be in service by 2013.