An experimental aircraft is an aircraft that is not type-certified and is used for research and development purposes. Experimental aircraft are often used to test new technologies or designs, and they can be significantly different from production aircraft. Some of the most famous experimental aircraft include the Bell X-1, which was the first aircraft to break the sound barrier, and the SpaceShipOne, which was the first privately funded spacecraft to reach space.
Experimental aircraft play a vital role in the development of new aviation technologies. They allow engineers and scientists to test new ideas and designs in a safe and controlled environment. Experimental aircraft have also been used to set world records and to push the boundaries of what is possible in aviation.