Drag is the aerodynamic force that is created when a solid body or object interacts with a fluid (liquid or gas) that moves in the opposite direction.

Drag also refers to the resistance between molecules of a fluid and a moving body or object.

For drag to happen, the body or object and the fluid must come into contact and be moving at different speeds. In the case of a quadcopter drone, the drag force happens when the quadcopter is moving and the air around it is moving in the opposite direction.

Since small quadcopter drones move at a slow pace, the drag force is very low because drag is related to speed.