In the Exploration of electric Aircraft Concepts and Technologies (EXACT) project, several hybrid-electric propulsion system concepts and possible aircraft configurations will be investigated and optimised in terms of their climate impact. DLR is conducting this conceptual study with a view to bringing an ecologically efficient, medium-haul aircraft into commercial service by 2040. Twenty DLR institutes from the fields of aeronautics, energy and atmospheric research are contributing their expertise to the study.