In this study, a GUI-based geometry deformation tool is developed for the efficient conceptual design of aircraft. This tool allows the designer to deform the configuration interactively by mouse operations. In addition, the user is able to estimate the flow around the deformed configuration quickly with computational fluid dynamics (CFD) solvers. This tool has the advantage that the user can deform the configuration and calculate the aerodynamic performance interactively in the same tool. Therefore, it enables deformation of the configuration according to the computational results and allows the creation of a high performance configuration within a short period of time. Furthermore, this tool is also coupled with an optimization engine. During optimization, the designer can confirm the configuration and its corresponding performance. If the change in the configuration does not meet the designer's requirements, the optimization can be stopped and the configuration can be deformed by hand. By coupling the configuration deformation tool and an optimization engines, the configuration satisfying the design goal can be found efficiently. This paper presents an overview of the development of this GUI tool.