A significant part of aeronautical science is a branch of dynamics called aerodynamics, which deals with the motion of air and the way that it interacts with objects in motion, such as an aircraft.
When you pour a liquid from one container to another, the liquid takes the shape of the container. The volume of the liquid is the same. The properties that solids and liquids share are that they both have definite volume.
The density of a liquid is constant. While both a solid and a liquid are condensed matters, liquids like gas are considered fluids. Liquids have many uses and one of them is as a solvent. They can dissolve solids and other liquids. As lubricants, they are used in engines, gears, and metalwork.