Final answer:
The subject of this question is physics and light aircraft require knowledge of physics principles.
Step-by-step explanation:
The subject of this question is Physics. Light aircraft require knowledge of physics principles, specifically those related to aerodynamics and flight.
Understanding the design and operation of aircraft, including factors such as size, wingspan, and flight characteristics, involves applying physics principles.
An example of a physics concept relevant to this question is the study of airfoil shape and lift, which determines the efficiency and performance of aircraft wings.