Which inventor's experiments significantly influenced the design of the airplane?

Sir George Cayley is often referred to as the "father of aerodynamics" and made foundational contributions to the design and understanding of aircraft. In the early 19th century, he conducted experiments with gliders and identified the four forces that govern flight: lift, drag, thrust, and weight. His systematic studies led to the design of a successful manned glider in 1853, illustrating the principles of powered flight and establishing the concept of aerodynamic lift, which was crucial for the development of heavier-than-air flying machines.

Cayley’s work laid the groundwork for future aviation pioneers, influencing thinkers and inventors who followed, such as the Wright brothers. His emphasis on testing models and understanding the physics of flight contrasts with the contributions of others in the options. For example, while Leonardo da Vinci conceived early ideas for flight and sketch designs, his work did not lead to practical experimentation or successful flight. Similarly, Albert Einstein’s theories of relativity pertain to physics rather than aeronautics, and Wernher von Braun focused on rocketry and space flight, rather than the fundamental principles of aerodynamics needed for airplane design.