Ornithopters are like birds having wings; earliest design for airplanes come from this concepts. This usually mimics the flapping motion of wings. Leonardo da Vinci’s ornithopter consisted of foot pedals and levers which help to get off the ground into the air having a pair of mechanical wings. ornithopters during its initial phase had never flew.
A glider is a fixed-wing aircraft that normally does not have an engine to give thrust when it flies in the air. It is supported in flight through the dynamic reaction of the air against its wings. Sir George Cayley designed the first successful glider to carry a human being. It had a layout of modern aircraft having a kite-shaped wing towards the front and at back an adjustable tailplane which considered to be horizontal stabilizers and vertical fin. The center of gravity was adjusted by a movable weight. Successful repeated flight with gliders was also made by Otto Lilienthal. Percy Pilcher built a hang glider.
The first successful motor-operated airplane was invented, built, and flown by wright brothers. This aircraft was mechanically controlled. It was a fixed-wing controlled and powered flight. The Control mechanism of aircraft consisted of a three-axis control system which made pilot to shear the aircraft efficiently and maintain its equilibrium. The methods and control system developed is still in use with all fixed wing aircrafts.
Biplanes are the airplanes that had two wings one above the other. Earlier successful airplanes both powered and unpowered were gliders. Biplane wing structure has a larger structural advantage than monoplanes, having a lighter wing structure, low wing loading, and a smaller span for a given wing area. However it produces more drag than a monoplane because of interface of airflow between the two wings and bracing of wing structures.
Douglas DC-3 was the most successful airliner in the initial stages of air transportation. It had a multiple spar wing and all-metal constructions making it very safe. It was reliable and inexpensive to operate. The airplane had a very good stability and was easy to handle with excellent single-engine performance.
The Boeing-737 and Airbus A320 are the most popular commercial passenger airplanes at present.
Future aircraft are based on the concept of all electric aircrafts, flying cars, environment friendly aircrafts which has reduced carbondioxide emmissions, drones , supersonic aircraft and autonomous aircrafts. Airplanes are also developed of engines with reduced fuel consumptions, drag, runway length and aircraft noise.
New innovative materials like Silicon Carbide fiber, Reinforced Sic Ceramic Matrix Composites are being developed for aircraft engines and related systems. These are ideal for high-performance machinery, like the aircraft engines which are operated for long times.