Boeing’s flight-test programme for its new 787 Dreamliner is running behind schedule, though the company insists that launch customer All Nippon Airways will have its first aircraft by 31 December.

The company was finally able to get the 787 airborne last December, but the plane is already two-and-a-half years behind schedule and has cost Boeing billions of dollars in penalties.

Minor delays and unexpected issues have meant that the crucial in-flight certification process with the Federal Aviation Administration has yet to begin. Jim Albaugh, chief executive of Boeing’s Commercial Airplanes unit said the company had built in some cushion to its test-flight certification schedule, but that some early snags have already eaten into some of that buffer.

Boeing recently completed what it described as a milestone test in which the Dreamliner was subjected to the socalled ultimate load test. During the test, the plane’s wings were flexed upward nearly 8 metres and the air frame was subjected to 150 per cent of the forces it would encounter during even the most severe conditions.

Officials said the initial results were positive but that “more extensive analysis and review are required before the test can be deemed a success.”