Aeronautical engineering was the original term before the broader term "aerospace" overtook it in usage, as flight technology advanced to include operating crafts in outer space. Aerospace engineering is largely about artefacts that fly - including airplanes, rockets, satellites or helicopters. It is also about how fluids flow, control systems, the strength of materials and improving strength. It also deals with how to design things so that they can be reliably built and maintained.
Aerospace engineers design, develop and test aircraft, spacecraft or missiles, and supervise their manufacture. Those who work with aircraft are called aeronautical engineers, and astronautical engineers are those working specifically with spacecrafts.
Aerospace engineers develop new technologies for use in aviation, defence systems and space exploration, and sometimes specialize in areas like structures, vehicle movement and control, propulsion systems, communications, and overall vehicle design. They also may specialize in a particular type of aerospace product, such as commercial aircraft, helicopters, military fighter jets, missiles, spacecrafts and rockets. These engineers might also be experts in celestial mechanics, aerodynamics, thermodynamics, acoustics, propulsion, or guidance and control systems.