Future flying wing aircraft. Illustration of a design for a future flying wing aircraft in flight over San Francisco and its Golden Gate Bridge and Bay. This design was produced by Northrop Grumman. It includes four engines embedded into the upper surface of the wing, providing shielding to reduce noise pollution. This design is one of several designs produced by the aviation industry in 2011 in response to a NASA challenge to design future aircraft that were more fuel efficient, less polluting, and less noisy. The designs were assessed by NASA Aeronautics Research Mission Directorate's Environmentally Responsible Aviation Project.