The Clean Sky 2 Technology Evaluator Project REIVON was the first comprehensive study investigating an optimisation of the global flight network combined with the selection of the optimal aircraft size and range for each flight, including size/range combinations not existing in today’s fleet. Besides the CO₂ reduction potential, also the impact on stakeholders was studied. The project started in 2021 and was just finalised at the end of 2023, carried out by Envisa, TAKS, The Manchester Metropolitan University and Hamburg University of Technology.