The design of aircraft has evolved over time from the classical design approach to the more modern computer-based design method utilizing multivariate design optimization. In recent years, aircraft concepts and configurations have become more diverse and complex thus pushing many synthesis packages beyond their capability. Furthermore, many examples of aircraft design software focus on the analysis of one particular concept thus requiring separate packages for each concept. This can lead to complications in comparing concepts and configurations as differences in performance may originate from different prediction toolsets being used. This paper presents the GENUS Aircraft Design Framework developed by Cranfield University’s Aircraft Design Group to address these issues. The paper reviews available aircraft design methodologies and describes the challenges faced in their development and application. Following this, the GENUS aircraft design environment is introduced, along with the theoretical background and practical reasoning behind the program architecture. Particular attention is given to the programming, choice of methodology, and optimization techniques involved. Subsequently, some applications of the developed methodology, implemented in the framework are presented to illustrate the diversity of the approach. Three special classes of aircraft design concept are presented briefly.