Aerospace/Aeronautical engineers design primarily aircraft, spacecraft, satellites, and missiles. In addition, they create and test prototypes to make sure that they function according to design. One of the newest branches of engineering, the field of aerospace engineering has changed dramatically since it began in the 19th century, and is expected to continue to evolve in pace with technological advancements. As such, the job outlook for aerospace engineers is equal to that for all occupations. Specifically, aerospace engineers are working to design more environmentally friendly aircraft which produce less noise pollution with enhanced fuel efficiency.