A small, reusable interceptor unmanned air vehicle (UAV), an avionics control system for the UAV, a design method for the UAV and a method for controlling the UAV, for interdiction of small scale air, water and ground threats. The UAV includes a high performance airframe with integrated weapon and avionics platforms. Design of the UAV first involves the selection of a suitable weapon, then the design of the interceptor airframe to achieve weapon aiming via airframe maneuvering. The UAV utilizes an avionics control system that is vehicle-centric and, as such, provides for a high degree of autonomous control of the UAV. A situational awareness processor has access to a suite of disparate sensors that provide data for intelligently (autonomously) carrying out various mission scenarios. A flight control processor operationally integrated with the situational awareness processor includes a pilot controller and an autopilot controller for flying and maneuvering the UAV.