CSG (Constructive Solid Geometry) model of aircraft should be generated for vulnerability analysis (Open-Source CAD S / W is used in BRL-CAD). Because in the early conceptual design phase of aircraft modeling, we have to create various shapes and a wide range of aircraft models to perform a vulnerability analysis of the data, in a short time and easy UI. This research is about implementation an easy UI software program to design a aircraft. and conversion from existing CAD model (CATIA V5) to CSG typed model (BRL-CAD).