The Boeing Company said yesterday that it was scrapping plans to build a futuristic high-speed plane called the Sonic Cruiser in favor of designing a fuel-efficient aircraft.

Boeing's announcement brings to an end one of the most imaginative — and some say quixotic — projects in recent aerospace engineering. Over the course of almost two years, Boeing executives said the company was putting together a new jet that would fly 15 to 20 percent faster than today's commercial planes.

But what really ignited the public's interest was the proposed design of the Sonic Cruiser. Looking like something from George Lucas's drawing board, it was pitched as a sleek bullet-shaped tube with two large wings in the rear and two smaller wings behind the cockpit.

What Boeing discovered was that there was little demand for the plane. With the airline industry mired in the worst downturn in its history and losing billions of dollars each year, no airline wanted to purchase an expensive jet geared toward business travelers. Such passengers were no longer paying for high-price tickets, and many airline executives raised doubts about whether extra speed could really pry open travelers' wallets.

Alan Mulally, the chief executive of Boeing Commercial Airplanes, said yesterday at a news conference in Seattle that Boeing would turn its attention to building a plane that would be 17 to 20 percent more fuel efficient than the 767. The company plans to introduce the plane in 2004, with a first delivery in 2008. There are no orders for the new plane yet.

"We will move the vast majority of our resources and energy to the super-efficient airplane," Mr. Mulally said. "I feel probably the future and what we can do and our direction is more clear now than ever before."

He said the new plane would look like the popular narrow-body 777 rather than Flash Gordon's planet-hopping rocket. He declined to give a cost estimate for research and development. The construction of the plane will not necessarily take place in the Seattle area, where Boeing has its commercial airplane operations.

Shares of Boeing rose 46 cents yesterday, to close at $32.71.

Boeing has been looking for years to develop a product that will help it pull out of a financial slump. Last October, it reported a 43 percent decline in third-quarter earnings from the period a year earlier. The company also scaled back its revenue projections for 2003 to $50 billion from $52 billion and said that it would deliver only 275 to 285 planes next year, down from earlier estimates of 275 to 300.

Mr. Mulally said yesterday that deliveries in 2004 would be about the same as in 2003. The company expects to deliver 380 planes this year.

Analysts said Boeing's announcement did not come as much of a surprise, since it had been hinting for a long time that it might use the research from its Sonic Cruiser project to develop another jet. And they said Boeing seemed to be making the right decision, given the bleak outlook of the marketplace.

"The Sonic Cruiser was a concept- car kind of idea," said Nicolas Owens, an analyst at Morningstar. "A lot of concept cars show up at the auto show and never hit the street. And that's O.K. It's a way to test the waters. There was a small, small market for the Sonic Cruiser to begin with."

Steven Binder, an analyst at Bear, Stearns, said: "Customers over the last six months have made it clear that they would prefer to have a low-cost conventional jet serving the 250-seat market. I think they can grab market share in the future with a low-cost conventional jet versus the Sonic Cruiser."

Mr. Mulally said that Boeing might be able to sell upward of 3,000 of the new jets and that they would have broad market appeal because they could be used as a replacement for various planes made by both Boeing and Airbus.

Airbus, which is based in Toulouse, France, has been gnawing away at Boeing's market share over the last several years. Airbus plans to deliver 300 planes next year, and it has already begun building the A-380, a 555-seat behemoth. In October, Airbus dealt a big blow to Boeing when it won a 120-jet order from EasyJet, the low-cost carrier based outside London.

Boeing said yesterday that it believed that it was making a smarter gamble than Airbus by betting that the increasing popularity of point-to-point service would mean that airlines would want smaller, more efficient planes rather than large ones built for big hub transfers.

"The average number of passengers per airplane has continued to go down," Mr. Mulally said. "I feel more confident than ever over the last three or four years that this is the next airplane Boeing needs to make."

This is the second time in the last several years that Boeing has shelved plans for a high-profile commercial jet project; it decided not to build a larger version of its 747 in favor of pursuing the Sonic Cruiser.