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A fixed-wing aircraft more commonly known as an airplane is a heavier-than-air craft where movement of the wings in relation to the aircraft is not used to generate lift. The term is used to distinguish from rotary-wing aircraft, where the movement of the lift surfaces relative the aircraft generates lift. Though technically all aircraft wings flex, and some aircraft have wings that can tilt, sweep back, or fold, if none of these movements are used to generate lift, the wing is considered to be a "fixed-wing".

Fixed-wing aircraft include a large range of craft from small trainers and recreational aircraft to large airliners and military cargo aircraft. Some aircraft use fixed wings to provide lift only part of the time and may or may not be referred to as fixed-wing.

Two necessities for all aircraft are air flow over the wings for lifting of the aircraft, and an open area for landing. The majority of aircraft, however, also need an airport with the infrastructure to receive maintenance, restocking, refueling and for the loading and unloading of crew, cargo and/or passengers. While the vast majority of aircraft land and take off on land, some are capable of take off and landing on ice, snow and calm water.

The aircraft is the second fastest method of transport. Commercial jet aircraft can reach up to 875 km/h. Single-engined aircraft are capable of reaching 175 km/h or more at cruise speed. Supersonic aircraft (military, research and a few private aircraft) can reach speeds faster than sound.

Conventional aircraft -- from small planes such as the Cessna 210 and Beech Bonanza to the gigantic Antonov 225 -- consist of a fuselage, one or more wings to provide the majority of lift, a tailplane for stability, and a one or more vertical surfaces at the tail for stability.

Each wing is a structure attached to the fuselage of the aircraft. Sometimes, the half of a wing on either side of the fuselage is referred to as a wing, e.g. left wing and right wing. Most aircraft are monoplanes having one wing structure for providing lift. Biplanes (two wings) or triplanes (three wings) were popular in the past, and some are still made for special purposes like aerobatics. Fuel is often stored in tanks in the wing and sometimes stored in the fuselage (or main body).

Fixed Parts
An engine (or engines): Also known as powerplants, engines serve to propel the aircraft on the ground and the air. Aircraft use a variety of engines, including turbine, reciprocating, and radial engines. The engines are usually located under or on the wings or attached to the fuselage. A few aircraft have engines attached to the vertical or horizontal stabilizer.

A tailplane is a small wing that provides positive or negative lift to stabilize the aircraft in flight. Most often it is configured to provide negative lift. It may be a fixed horizontal stabilizer with a movable elevator or a stabilator that rotates on a shaft to change the angle of incidence.
The vertical stabilizer is a small vertical wing that is usually attached to the rear of the fuselage. Some aircraft have two vertical stabilizers attached to the horizontal stabilizer or boom structures. A rudder is attached to the vertical stabilizer.

Movable parts
Ailerons are movable surfaces on the wings of the aircraft. They always act at the same time, but in inverse directions, so that the aircraft can be turned along its longitudinal axis. This movement is called roll. Because roll changes the direction of lift of the wings, it is the primary method of changing the direction of travel. Many larger aircraft use spoilers to achieve the same effect.
The elevators are located on the horizontal stabilizer to control the rotation around the lateral axis called pitch. The elevator and horizontal stabilizer may be combined into a stabilator.
On delta-wing aircraft the ailerons and elevators are combined together to perform the same actions and are called elevons.
The rudder is located on the vertical stabilizer and controls movement around the vertical axis called yaw.
The landing gear allow the aircraft to take off and land. They usually retract during flight to reduce drag; however, on smaller aircraft the gear may be fixed. Some aircraft are equipped with special landing gear, such as pontoons or skis, to allow them to land on water, snow or ice.
The flaps change the profile of the wing of the aircraft, maximizing lift and control of the speed of the aircraft in air, particularly in operations of low speed - especially important in landing and take-off.

Other parts of aircraft include trim tabs, air brakes, spoilers, winglets and canards.
Unconventional aircraft have been built in a variety of forms. For example: lifting body, canard, V-tail, flying wing and anything by Rutan.

Flight
An aircraft flies due to the aerodynamic reactions that happen when air passes over the wing.
If a cross-section of an aircraft wing is viewed, the top of the wing can be seen to be curved, while the bottom of the wing is less curved or straight. This shape, called an airfoil or aerofoil, creates lift when a wing travels through the air.

Lift is created as an airstream passes by something which deflects it downward. The force created by this deflection of the air creates an equal and opposite force upward on the wing according to Newton's third law of motion. The deflection of airflow downward during the creation of lift is known as downwash.

Nearly any shape will produce lift if curved or tilted with respect to the air flow direction. However, most shapes will be very inefficient and create too much drag. One of the primary goals of wing design is to devise a shape that produces the most lift while producing the least lift-induced drag.

Propeller Aircraft
Smaller and older propeller aircraft make use of reciprocating internal combustion engines that turns a propeller to create thrust. They are quiet, but they fly at lower speeds, and have lower load capacity compared to similar sized jet powered aircraft. However, they are significantly cheaper and much more economic than jets, and are generally the best option for people who need to transport a few passengers and/or small amounts of cargo. They are also the aircraft of choice for pilots who wish to own their own aircraft.

Turboprop aircraft are a halfway house between propeller and jet: they use a turbine engine similar to a jet to turn propellers. These aircraft are popular with commuter and regional airlines, as they tend to be more economical on shorter journeys.

Jet Aircraft
Jet aircraft make use of turbines for the creation of thrust. These engines are much more powerful than a reciprocating engine. As a consequence, they have greater weight capacity and fly faster than propeller driven aircraft. One drawback, however, is that they are noisy; this makes jet aircraft a source of noise pollution.

The jet aircraft was developed in England and Germany in 1931. The first jet was the Heinkel He 178, which was tested at Germany's Marienehe Airfield in 1939. In 1943 the Messerschmitt Me 262, the first jet fighter aircraft, went into service in the German Luftwaffe. In the early 1950's, only a few years after the first jet was produced in large numbers, the De Havilland Comet became the world's first jet airliner, but was removed from service due to structural inadequacies discovered after numerous pressurization and depressurization cycles.

Wide-body aircraft, such as the Airbus A340 and Boeing 777, can carry hundreds of passengers and several tons of cargo, and are able to travel for distances up to 13 thousand kilometers.

Jet aircraft possess high cruising speeds (700 to 900 km/h) and high speeds for take-off and landing (150 to 250 km/h). Due to the speed needed for takeoff and landing, the jet aircraft makes use of flaps and leading edge devices for the control of lift and speed, and has engine reversers (or thrust reversers) (to direct the airflow forward) to slow down the aircraft upon landing, as well as the wheel brakes.

Supersonic Aircraft
Supersonic aircraft, such as military fighters and bombers, Concorde, and others, make use of special turbines (often utilizing afterburners), that generate the huge amounts of power for flight faster than the speed of the sound. The design problems for supersonic aircraft are substantially different to those for sub-sonic aircraft.

Flight at supersonic speed creates more noise than flight at subsonic speeds, due to the phenomenon of sonic booms. This limits supersonic flights to areas of low population density or open ocean. When approaching an area of heavier population density, supersonic aircraft are obliged to fly at subsonic speed.

Due to the high costs, limited areas of use and low demand there are no longer any supersonic aircraft in use by any major airline. The last Concorde flight was on 26 November 2003. It appears that supersonic aircraft will remain in use almost exclusively by militaries around the world for the foreseeable future, though research into new civilian designs continues.

Source: www.airliners.net