Mankind has extended efforts in perusing the skies with man-made flying objects for over 2,000 years. The history of aviation began with the invention of kites and gliders, before emerging to the multimillion-dollar aircraft industry of the modern era. The origin of the first man-made flying objects were kites circa 200 B.C. in China.
Leonardo da Vinci expressed his dream of flight in several of his paintings circa the 15th century; however, his dream never manifested into a constructed flying vessel. During the 17th and 18th centuries, the discovery of hydrogen led to the first development of the hydrogen balloon, which carried people away at high altitudes and across several miles.
In the 19th century, tethered balloons were used to transport people and observe battles safely above ground as they took place. Other scientific discoveries developed a variety of theories in mechanics that became the backbone of Isaac Newton's laws of motion and fluid dynamics, which eventually led to the development of modern aerodynamics. In the early 20th century, gliders became the groundwork for massive aircraft, engine technology, and further developments in aerodynamics.