Page "Aeronautics" Paragraph 2

One of the significant parts in aeronautics is a branch of physical science called aerodynamics, which deals with the motion of air and the way that it interacts with objects in motion, such as an aircraft.

The term " aviation " is sometimes used interchangeably with aeronautics, although " aeronautics " includes lighter-than-air craft such as airships, and includes ballistic vehicles while " aviation " does not.