Flight

Flight is the process by which an object achieves sustained movement either through the air (or movement beyond earth's atmosphere, in the case of spaceflight) by aerodynamic generating lift, propulsive thrust or aerostatically using buoyancy. Forces relevant to flight are These forces must be balanced for stable flight to occur. The stabilization of flight angles (roll, yaw and pitch) and the rates of change of these can involve horizontal stabilizer (i.e. 'a tail'), ailerons and other movable aerodynamic devices which control angular stability i.e. flight attitude (which in turn affects altitude, heading). The most successful groups of living things that fly are insect, bird, and bat. The extinct Pterosaur, an order of reptiles contemporaneous with the dinosaur, were also very successful flying animals. Each of these groups' wing evolved independently. The wings of the flying vertebrate groups are all based on the forelimbs, but differ significantly in structure; those of... full article at wikipedia