The first Boeing 787 is expected to be delivered in 2008

The "stretch" version of the 250-seat plane will seat 300 passengers and will begin flying in 2012.

Boeing said Emirates and about a dozen other airlines had been asking about such a plane.

It has staked much of its future on the success of the 787, and has been competing fiercely for orders with European rival Airbus' A350 aircraft.

Fuel-efficient

Boeing took 235 orders for the Dreamliner in 2005 during a bumper year for the industry.

It expects to begin production of the 787 in 2007 and deliver the first of the aircraft the following year.

The company says its long-range 787 aircraft, which is designed to seat up to 250 passengers, will be 20% more fuel-efficient than similar mid-sized planes.