The aviation industry faces the challenge of minimizing its environmental impact without compromising performance and safety. In this context, lightweighting and composite technologies are becoming increasingly important as key technologies for more sustainable aviation. This article examines the role of lightweight design using composite technologies in reducing the weight of aircraft, leading to improved fuel efficiency and lower emissions, as well as conserving resources by using less material. The current developments including their opportunities and challenges are highlighted. In addition, the advancing technologies for production and the integration of composites in aircraft structures as well as for using them in the context of new propulsion systems, including hydrogen systems, are presented. A particular focus is on analyzing the impact of these technologies on the environmental sustainability of aviation and their contribution to achieving sustainability goals. By taking a holistic view of these topics, it will be made clear how composites and lightweight design can make a decisive contribution to steering the aviation industry onto a sustainable course for the future.