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.
All of these are gases and yet have much higher molecular weights than water does. However, none of these can hydrogen bond, and that is why they are gases, whereas water is a liquid. Of course, at high temperatures water is a gas (steam) and at low temperatures water is a solid (ice). See the Web Links for more information about intermolecular forces. Why is water at room temperature a liquid?