The recent developments in fast additive manufacturing, such as rapid 3d-printing of composite materials, presents opportunities for the manufacturing of small unmanned aerial vehicles (UAVs) that are tailor-made for the specific mission needs. This paper presents a novel framework for mission-oriented, modular design and construction of mini-UAVs using additive manufacturing. The outcome is a manufacturing method which is suitable for a parametric design that can be tailored for the specific mission requirements and rapidly constructed using additive manufacturing techniques. We show how additive manufacturing enables an agile design methodology by allowing fast and efficient iteration of prototypes during the design process.The proposed framework is demonstrated by presenting the iterative design of a tail-sitter hybrid VTOL vehicle, where the wing-tip geometry and the wing dihedral angle went through several changes. Additionally, we have extensively validated the performance of the resulting vehicle design through flight tests in a motion capture facility and outdoors. Finally we have shown several other configurations of vehicles such as quad-rotors, and a fixed-wing that can also take advantage of the proposed manufacturing method.