Safe Landing (https://safe-landing.org) works internationally, but with a UK focus. It represents "climate concerned aviation professionals" including pilots, cabin crew, airport staff, engineers and factory operators and calls for early adoption of regulations to reduce emissions and a plan to support workers during any transition to secure their careers. Workers’ Assemblies follow the concept of deliberative democracy to advise on political and aviation company decisions. Most technical options (new aircraft and new fuels) for reducing greenhouse gas emissions from aviation have serious limitations. Hence, technology won't safe us and cannot be an excuse to delay action. Nevertheless, some options are available now (!), but seem to be overlooked by industry, because they do not come handy: a) to fly lower (or higher) to reduce contrails, b) de-aromatization of fossil jet-fuel with hydrotreatment for both climate and health, c) to reduce air travel (with various measures).
Hamburg Aerospace Lecture Series --- Collection of Presentations --- http://www.AeroLectures.de