Aeronautics is defined as the science in which the design, manufacturing and study of aircrafts capable machines and principles of operating rockets and aircraft machines within the atmosphere is involved.
The word Aeronautics simply means "sailing the air" and referred entirely to the science of operating the aircraft.
Aeronautics is classified into 3 wings. They are
Aviation: It is an art or practice of aeronautics. Initially aviation is just meant for heavier than air flight but presently it also includes flying in balloons and airships
Aeronauticsl Science: Aeronautical science is the practical theory of aeronautics and aviation, including navigation, operations, human factors, air safety and includes sciences propulsion & aerodynamics.
Aeronautical Engineering: It is the application of design, model and constuction of aircrafts which includes operation of aircrafts and the forces acting on aircraft.