This paper presents an overview of a project called “Modelling and Simulation Tools for Systems Integration on Aircraft (MISSION)”. This is a collaborative project being developed under the European Union Clean Sky 2 Program, a public-private partnership bringing together aeronautics industrial leaders and public research organizations based in Europe. The provision of integrated modeling, simulation, and optimization tools to effectively support all stages of aircraft design remains a critical challenge in the Aerospace industry. In particular the high level of system integration that is characteristic of new aircraft designs is dramatically increasing the complexity of both design and verification. Simultaneously, the multi-physics interactions between structural, electrical, thermal, and hydraulic components have become more significant as the systems become increasingly interconnected.The aim of MISSION is to develop and demonstrate an integrated modeling, simulation, design and optimization framework incorporating Model-Based Systems Engineering (MBSE) principles oriented to the Aerospace industry. This framework will holistically support the design, development and validation process of an aircraft, starting from conceptual aircraft-level design, toward capture of key requirements, system design, software design, integration, validation and verification. In order to achieve this goal, MISSION will deliver a core modeling and simulation environment, primarily based on the Modelica language for modeling of multi-physics systems, which incorporates dedicated platforms and toolsets for aircraft-level design and optimization, system-level design and optimization, model-based controls and virtual testing. The paper outlines the technical development program, the challenges being addressed and the benefits that this framework will bring to the Aerospace industry.