<p>Using lightweight materials in aircraft structures, especially carbon fiber reinforced polymer (CFRP), can be an option for achieving aviation's ambitious emission reduction goals. However, using CFRP can be associated with adverse environmental and economic impacts, which can relativize its potential benefits. Nevertheless, the extent of the potential advantages and disadvantages of the increased use of CFRP in the entire airframe is still uncertain, as existing studies relate to specific airframe components or estimated weight savings. This article aims to close this gap by developing detailed life cycle inventories (LCIs) for aircraft with CFRP structures and analyzing the environmental and economic impacts during aircraft production and use. Furthermore, potential reinforcement effects from using sustainable aviation fuels (SAFs) in such aircraft are investigated to determine the overall environmental and economic impacts. For this purpose, three aircraft configurations with different CFRP content are modeled using the aircraft design program “Preliminary Aircraft Design and Optimization”. Afterward, detailed LCIs are developed, and life cycle assessment and environmental life cycle costing are applied. Subsequently, an analysis is conducted where SAFs replace fossil kerosene to investigate the potential for further reductions of environmental and economic impacts. The results of the analysis indicate that increasing the CFRP content in the airframe reduces environmental impacts during production and use. Despite higher production costs, more cost-effective flight operations are possible. Additionally, there is a reinforcement effect through using SAFs in aircraft with increased CFRP content, which can further reduce climate-damaging emissions by several magnitudes more compared to lightweight materials alone.</p>