Boeing also plans to simultaneously develop two versions of the plane, with both to enter service in 2008, said Mike Bair, the Boeing vice president leading the 7E7 program.

By weight, the jet will be made of 50 percent composite materials, 20 percent aluminum, and 30 percent titanium, steel and other materials, Bair said in a telephone conference with reporters. That compares with 12 percent composites, 70 percent aluminum and 18 percent other materials in Boeing's existing 777 jetliner.

By using more composites, Boeing hopes to cut costs for airlines, along with its own manufacturing expense.

An airplane body made out of composites, essentially high-tech plastics, will require far less heavy maintenance, Bair said. In addition, workers building the jet can snap together much larger pieces rather than rivet smaller parts with hundreds of thousands of fasteners, he said.

Boeing won't decide until next year whether to formally launch the 7E7 program.

However, the company plans to host representatives from more than 40 airlines next week to show off a recently completed mock-up of the plane's interior and update them on 7E7 design.

"We're getting a really good sense of how this airplane is going to go together," Bair said.

Bair said Boeing now plans a base model that will seat about 200 passengers with a range of nearly 9,000 miles.

The wing span will be 193 feet and the fuselage about 182 feet. The plane is expected to have a gross maximum takeoff weight of 452,500 pounds.

At the same time, the company plans to develop a shorter-range version that will go less than half the base model's distance, about 4,000 miles, but still capable of a New York-to-Los Angeles flight. The airplane would carry about 300 passengers in a single-class configuration, Bair said.

As the market warrants, Boeing will develop a stretch version of the airplane, about 20 feet longer, that will seat 50 more people and have a range of just over 9,500 miles.

Boeing estimates a market for about 2,500 of the 7E7s, with 1,000 each for the base model and stretch version and 500 for the shorter-range model, Bair said. Customers are expected to mainly be domestic and regional airlines in Japan and China.

Boeing currently builds six commercial jet models: the 717 short-haul jet in Long Beach, Calif.; single-aisle 737s and 757s in Renton; and twin-aisle 747s, 767s, and 777s in Everett.

The fuel-efficient 7E7 would eventually replace the company's twin-aisle 767 and single-aisle 757 planes. Boeing has already announced it plans to end new production of 757s late next year. The variants described by Bair resemble the 767 in passenger capacity and range.

Bair did not offer any updates on the company's search for where it will build the 7E7. The company is on track to select a site by the end of the year, although the decision could spill over into early 2004, he said. Boeing's board is also expected to decide whether to offer the airplane for sale to airlines around that time.

"One of the things that will make this a little bit of a complicated process is that all the sites are different," he said. "They have different strengths and different weaknesses and we have a very rigorous process to try to go through and evaluate all of the criteria and establish essentially a scoring system on how these things stack up."

Bair also said the company expects to have major design completed in early or mid 2005, with major assembly starting in 2006. The jet's first flight would come in 2007 with certification and delivery in mid-2008.