Boeing Co's carbon-composite 787 Dreamliner is set to fly in the fourth quarter. The test flight, now two years behind schedule, could be vindication for Boeing, which hopes to repair its credibility after the delays.

Here are a few facts about the 787 Dreamliner:

* The 787 Dreamliner promises greater efficiency through the use of durable, light-weight composite materials.

* Planes in the 787 family have list prices between $150 million and $205.5 million.

* Boeing has taken orders for 850 Dreamliners from 56 customers.

* The most recent delay results from a structural problem within the side-of-body joint of the aircraft, which is the connection of the wing to the fuselage.

* The 787 will use 20 percent less fuel for comparable missions in similarly sized airplanes.

(Reporting by Kyle Peterson, editing by Matthew Lewis)