Aerospace engineering deals with the design, construction, and science behind the forces and physical properties of aircraft, rockets, flying craft, and spacecraft. The field also covers their aerodynamic characteristics and behaviors, airfoil, control surfaces, lift, drag, and other properties. Aerospace engineering is not to be confused with the various other fields of engineering that go into designing these complex craft. For example, the design of aircraft avionics, while certainly part of the system as a whole, would rather be considered electrical engineering, or perhaps computer engineering. The landing gear system on an aircraft may fall into the field of mechanical engineering, and so forth. It is typically a large combination of many disciplines that makes up aeronautical engineering.