Which type of flight capability allows a rotary-wing aircraft to begin and end its flight without a runway?

The ability of a rotary-wing aircraft to begin and end its flight without the need for a runway is characterized by Vertical Takeoff and Landing (VTOL) capability. VTOL allows these aircraft, such as helicopters, to ascend vertically from a hover and descend vertically to a hover before landing. This capability is essential for operations in confined spaces or locations where traditional runways are not available or practical.

In contrast, Landing Gear simply refers to the structure of the aircraft that supports it on the ground and does not specifically pertain to the capability of initiating or concluding flight in the vertical manner. Short Takeoff and Landing (STOL) refers to aircraft that require a short distance to take off and land but still need a runway, while Conventional Takeoff and Landing (CTOL) implies the use of standard runways and requires longer distances to operate effectively.