An aircraft is a type of vehicle that is able to fly. They utilize static lift or airfoils top counteract the force of gravity, thus creating lift and flying. In some cases downward thrust is used as in jet engines. Missiles and rockets, although they fly through the atmosphere, are not considered to be aircraft because they use rocket propellant instead of aerodynamics to create lift. The cruise missile stands as an exception to the rule because it does in fact rely on air for flying. The men and women who operate these aircraft are called aviators or more simply put pilots.
There are manned aircraft, which are flown manually by a human. Then there are un-manned vehicles such as the military drone which is flown by a person remotely. Some of these remote operates may actually be thousands of miles away from the aircraft that they are flying. Aircraft are classified by different criteria that depend on their lift type, method of propulsion, and their usage. What has amazed humans since the dawn of flight was the ability to take something that is heavier than air and make it fly. This comes down to aerodynamics and technology. The shape a wing is not flat, but curved. The air has to travel over the top of the wing (which curved).
This causes the air below the wing (where it is flat) to travel faster than the air on the top, thus creating the lift. The most common type of aircraft in use today is the fixed-wing. These fixed winged aircraft has one row (in some cases, the bi-plane, two) of wings that do not move. These fixed-wing craft utilize the above mentioned method for lift. The other common type of aircraft is the rotorcraft. These planes use a propeller with specially shaped blades that when combined with the wing shape cause it to lift. The simple kite, which we all played with as children, was the first type of fixed-wing aircraft developed by the Chinese sometime around 500 BC.
There is also an aircraft that uses no propulsion. These are called gliders. A glider must be attached to another craft that can tow it up to the desired altitude. Then the glider is released and piloted manually by someone inside of it. The wing shape, as afore mentioned, gives is some lift and the craft glides through the sky effortlessly. Because there is no form of propulsion the glider will slowly descend and eventually land on an airfield just as its faster cousin, the air plane.
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