An Object-Oriented Framework for Flexible Design of Fixed-Wing Aircraft

Climate impact is becoming an important design driver in aviation, alongside traditional performance requirements. At the same time, fixed-wing aircraft concepts are growing more complex as designers explore new geometries, propulsion systems, and energy technologies. These trends increase the coupling between configuration, systems, and mission, and create a need for flexible design frameworks that can handle this complexity in a consistent way. This paper presents ASPECT (Aircraft Sizing and Performance Estimation Code and Toolkit), an object-oriented, modular framework for the conceptual and preliminary design of fixed-wing aircraft. ASPECT represents aircraft as assemblies of reusable components and supports integrated evaluation of performance and environmental impact within a mission-based workflow. Its capabilities are illustrated through three applications covering battery-electric, hybrid-electric, and conventional turbofan transports. Together, these studies demonstrate how ASPECT can be used to explore diverse fixed-wing configurations while linking design and operating choices to both performance and climate-related outcomes.