The world is turning green. The focus on environmental issues increased during the last years, in particular the effect that rising levels of CO2 in the Earth's atmosphere has on global warming. Reducing environmental impact becomes a business imperative. But aviation is still considered one of the most difficult transport sectors to decarbonize. Carbon emissions from aviations accounts for around 2.5% of global emissions. Related to the projected growth of aviation after the pandemic, an increase in emissions is expected. Therefore the idea of "green aviation" and environmentally sustainable practices becomes more and more important.