The US aircraft maker Boeing has said it is shelving plans to build its high-speed Sonic Cruiser passenger jet aircraft.

Instead the company has said it will concentrate on a more traditional fuel-efficient aircraft.

Boeing announced its plans to build the Sonic Cruiser in March 2001.

But no airline has ordered the plane and many carriers are now struggling to survive following the post-11 September slump in air travel.

New focus

The Sonic Cruiser was designed to carry about 250 passengers and cut flight times by between 15% and 20%.

But Boeing's chief executive of commercial airplanes, Alan Mulally, said a decision was made last week to switch priorities.

"We will continue to look at (a Sonic Cruiser)," he said.

"We are going to move the vast majority of our resources over now to the super efficient airplane, that is going to be our focus."

The new plane is expected to be launched in 2004 and enter service in about 2008.

Industry downturn

Following the events of 11 September last year, the air industry was plunged into crisis as commercial airlines saw passenger numbers drop dramatically.

Two US airlines, US Airways and United Airlines, have had to file for bankruptcy protection.

Boeing has also suffered from the downturn.

It has cut thousands of jobs and has already scaled back next year's plane delivery plans to between 275 and 285 planes.

Mr Mulally said on Friday that Boeing expected a similar number of deliveries in 2004, with an increase in production in 2005.

"It all depends on how safe we keep the world, how fast we get the traffic coming back and how quickly airlines can repair their balance sheets and balance capacity with demand," said Mr Mulally.

"Hopefully with where we are, we are at the bottom of this cycle."