Drones are common technology today. But people have been interested in small flying machines for a long time (since the early 1900s). In the 1950s, helicopters were modified to be devices similar to today’s drones. This led to the invention of so-called quadcopters or quadrotors. They form some early models of today’s drones.
The image below shows a quadrotor carrying a human, discussed in the January 1958 edition of Popular Mechanics.
Most of the current day drones do not carry a human being, unlike the one shown above in the image.
Is a quadrotor the same as a drone? The contemporary definitions are more complex. Below is the description of the quadrotor compared to the drone (from this source) :
Quadcopter, on the other hand, is a much more specific qualifier compared to drones. The term quadcopter specifically describes an uncrewed rotary wing aircraft that can take flight using four rotors each consisting of a motor and propellers. Quadcopters are sometimes referred to as quadrotors as well. Unlike traditional fixed wing aircraft or helicopters which rely on engines and/or tail rotors to take flight, quadcopters have neither.
Inference: It is often worth visiting the past to innovate for the future!
VISMAYA - History & Philosophy of Physics 