What defines a rotorcraft in the context of aviation?

A rotorcraft is specifically defined by its method of generating lift, which is achieved through the use of rotating blades or rotors. This distinguishing feature sets rotorcraft apart from other types of aircraft, such as fixed-wing planes, which rely on their wings for lift rather than rotating blades. Rotorcraft can take many forms, including helicopters and similar aircraft, and are recognized for their unique capability to perform vertical takeoffs and landings, hover in place, and maneuver easily in confined spaces. This versatility is a fundamental aspect of rotorcraft operations, making them essential for a variety of missions, including search and rescue, medical transport, and aerial firefighting.

The other options do not accurately capture the defining characteristic of rotorcraft. For example, a fixed-wing aircraft is not associated with rotor systems; heavy-lift transport refers to a role rather than a definition, while operating at high altitudes describes a performance characteristic not specific to rotorcraft.