The perception of environmental problems especially global warming is more than ever an issue, especially in this day and age when reaching agreements on today's climate targets is a challenge and a topic of concern among European citizens of all ages. Associated effects of global warming, like extreme weather events, are driven primarily by the emission of exhaust gases (especially CO2, nitrogen oxides and methane) and water vapour creating contrails. Hence, reducing emissions to preserve the environment, while keeping the mobility is a central society need now and in the future. To reduce the emissions in short and medium term, changes in flight trajectory design and ATC operations are an appropriate means. Thereby, the flight trajectories are influenced on one hand by environmental and aircraft parameters, and on the other by ATC driven parameters, like route length or usable altitudes. During flight execution, re-planning on board of an aircraft using the flight management system enables to consider dynamic effects on the tactical level, like changes in the weather situation. For the efficiency of such a greener trajectory, it is necessary that the trajectory can be flown in the planned way, even under the actual traffic situation controlled by ATC, which today is often not the case. The overall objective of the cooperation of Chinese and European partners in GreAT is to reduce the fuel consumption and gas emissions during “gate-to-gate” flight phases through developing and assessing environment-friendly air traffic operational concept, adaptive airspace and green trajectory optimization technologies, and supporting avionic systems. Evaluation campaigns between the European partners and in combination with the Chinese partners through cross evaluations are planned to validate the proposed concept and show a potential significant reduction of the aviation’s impact on climate change.