Boeing has delayed the delivery of its 787 Dreamliner for the third time, as work on the aeroplane hit problems.
Dreamliner's first flight has been pushed back to the end of the year due to slower-than-expected completion of work and unexpected rework, Boeing said.
The Seattle-based firm has also extended testing time for the new aircraft by two months.
The US plane developer said it now targets approximately 25 deliveries in 2009, with the first delivery planned for the third quarter of 2009.
The first-year delivery will be followed by a more gradual ramp up to full-rate production than previously planned, Boeing added.
British Airways (BA) and Virgin have both ordered the planes, which have been designed with a carbon-composite fuselage, making them 20 per cent lighter than other planes of similar size.
Lighter planes use less fuel and are therefore cheaper as well as being greener.
BA and Virgin said they are looking into their options, which could potentially include compensation.
"We deeply regret the disruption and disappointment these changes will cause for our customers, and we will work closely with each of them to minimize the impact," said Boeing commercial airplanes president Scott Carson.
"We have taken significant action to improve supply chain and production system performance, such as our investment in Global Aeronautica, but based on our assessment, the prudent course is to proceed with a more gradual ramp up to full-rate production," Mr Carson added.
Boeing said while research and development costs will likely increase as a result of the 787 schedule change, the company expects no change to 2008 earnings guidance.