Boeing has delayed the first flight of its 787 Dreamliner aircraft until 2009. The previous timetable was for before the end of 2008.
It is the fifth substantial delay to the Dreamliner's first flight, which was originally planned for summer 2007.
Boeing has blamed the delay on a strike by machinists, which ended on Sunday after 58 days.
It also blamed a problem with the installation of the fasteners that hold the aircraft together.
The project has been plagued by delays due to problems with suppliers and shortages of parts.
The BBC reports some customers have been told they will have to wait two years longer for their aircraft than originally promised.
The Dreamliner is the first airliner to be made from a mixture of carbon fibre and plastic. The materials make it lighter and more fuel-efficient than other aircraft, and allows it to travel further without refuelling.