The prospects for green aviation by 2050

The continued emission of greenhouse gases presents an existential threat to civilization on our planet. Although the aviation sector of the global economy con-tributes only a small percentage of the total greenhouse gas emissions it will become increasingly important to decarbonize this sector no later than 2050 if the danger of irreversible climate change is to be averted. In this special issue an attempt is made to provide the readers of "Progress in Aerospace Sciences" with easy access to the views of twentyfive active researchers in the field of sustainable aviation in eight comprehensive review papers on the current status and the challenges to achieve the transition to green aviation by mid-century.