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.
Water is not like other liquids. It isn't, well, a normal liquid. In other liquids, the basic principle holds true that heated liquids expand and cooled liquids contract. But water doesn't exactly work the same way. Water does expand when heated and contracts when cooled, but not at all temperature levels.