TOKYO, JAPAN - Japan's All Nippon Airways, the launch customer for the Boeing 787 Dreamliner, said Wednesday it was 'disappointed' with a fifth delay in the first flight of the next-generation plane.

Boeing Tuesday delayed the first flight and delivery of its 787 Dreamliner to reinforce the structure of the aircraft, the latest setback in a programme seen as a key to the US aerospace giant's future.

'We are disappointed that the first flight of the 787 will be postponed, and urge Boeing to specify the schedule for the programme as a whole as quickly as possible,' All Nippon Airways (ANA) said in a statement.

Boeing had planned for the much-delayed Dreamliner to have its maiden flight by June 30 on a schedule that would allow delivery of the plane to ANA in the first quarter of 2010.

ANA has ordered a record 50 of the jets. The early 2010 launch was already roughly two years later than initially promised.