Aeronautics is a branch of engineering science related to the knowledge of Air planes and Helicopters and Space shuttles and their flights. Children or high school graduate may have a dream to land on a moon or see the earth from thousands of miles above the horizon or could have wings like a bird and can fly anywhere they want so they have a chance to fulfilling their dream by getting a degree in Aeronautics or Aviation engineering.
Aeronautics and Aviation both are vast fields you can get into plenty of different branches of each of them.
Aeronautics: Aeronautical engineers are mostly into the structure of aircrafts/ spacecraft designing them and pattern of their flight according to their design. Different airplanes are used for different tasks so engineers have sometimes had to be specific to the purpose for that aircraft. Airplanes used by military, fighter jets and also the missiles because a flight of a missile and science of trajectory is very important as the missiles need to hit a particular target with accuracy.
So you could after studying become an inventor too of the new aircrafts and missiles also there is study involve that allows you to think to use best possible material for the aircrafts and missiles that is easily available cheap to buy and durable too.
Aviation: is mostly related to the maintenance of air planes and their systems involving their communications and propulsion systems also if there is a fault occurs in flying pattern of the aircraft. These are basically known as technicians and there work is tough than engineers as to find a fault is a difficult thing if everything of airplane is previously tested and authorized for flying.
You could also become pilots if you have completed the degree in certain age as for pilots a young age is required although commercial planes have pilots of old age but to hire them they must be young as they have no experience for the flights. The demand for aerospace pilots and engineers is always high because the industry has expanded too much. There will be job opportunities available not only in your home country but also internationally. It is a very good field for you if you have interest in planes and flying.