The study, design, and manufacture of air flight-capable machines, as well as the techniques of flying aircraft and rockets within the atmosphere, constitute aeronautics. The British Royal Aeronautical Society identifies “aeronautical Art, Science, and Engineering” and “The profession of Aeronautics (which expression includes Astronautics).”
Although the term originally referred to only operating an aircraft, it has since expanded to encompass business, technology, and other aspects related to aircraft. Aeronautics and aviation are sometimes used interchangeably, but aeronautics includes lighter-than-air craft, such as airships, and ballistic vehicles, whereas aviation does not.
As part of aeronautical science, there is a field of dynamics called aerodynamics, which deals with the way air moves and how it interacts with objects in motion, such as aircraft.