What type of UAS combines the features of rotors and fixed-wing systems?

The type of UAS that combines the features of rotors and fixed-wing systems is a powerlift. This category of drone utilizes the vertical take-off and landing capabilities provided by rotors, much like a rotorcraft, while also possessing fixed-wing components that allow for efficient forward flight similar to an airplane. This hybrid design facilitates advantages such as vertical take-off and landing in confined spaces, as well as enhanced aerodynamics during longer flights. This makes powerlifts particularly useful in a variety of applications including surveying, cargo transport, and search and rescue operations, as they can efficiently transition between hovering and forward flight.

In contrast, a quadcopter is purely a rotor-based system that lacks fixed-wing characteristics, while a helicopter also relies solely on rotor systems and does not incorporate fixed-wing features. Finally, a glider is a fixed-wing aircraft that does not utilize rotors at all, focusing instead on soaring and gliding through the air without propulsion. Each of these options lacks the hybrid characteristics that define a powerlift UAS, making it the correct answer.