Modern and complex aerospace systems are being developed and optimized to enable the transition towards more-electric and/or all-electric aircraft. The integration of these systems in new generation aircraft and the multi-physics interactions between them are causing a greater complexity in both the design and verification processes. To face this complexity, several tools that can support integrated modelling, simulation, optimization and testing across all the stages of the system design are being developed. In this context, the European Commission launched the Clean Sky 2 Joint Technology Initiative. This program is a public-private partnership which provides funding for research and development of the processes, tools and technologies that will enable the aviation industry to increase the demand for aircraft with reduced fuel consumption, noise and emission of pollutants.