The current impact of the aviation industry on climate change poses little choice for aviation companies but to invest in sustainability. One way to do this is to develop and implement sustainable innovations in aircraft. However, the question is how it can be validated whether an innovation is sustainable. To do so, this research uses sustainability assessment methodologies and investigates, how the integration of sustainability assessment tools can support the decision-making process regarding investment in sustainable innovation. It presents the methodology for the sustainability assessment of sustainable innovation for aircraft while using two tools - Life Cycle Assessment (LCA) and Cost-Benefit Analysis (CBA). The first one is to assess the environmental impacts of an innovation, the second one is to determine its financial and also social implications. The chosen sustainable innovation, upon which the case study is developed and the methods are tested, is the bio composite material for usage in aircraft interiors. In particular, the viability of replacing conventional composites in Boeing 787-8 aircraft business class seats with bio composites is considered. The thesis is conducted in collaboration with Collins Aerospace, which is the manufacturer of products for aircraft. Before realizing sustainability assessment, the technology is analysed using theoretical frameworks. In particular, the analysis is developed on technology drivers, challenges, and the current stage of development in the aviation and automotive industry. After that, the specific bio composite suitable for aircraft interior - geopolymer panel created in an EU project - is chosen for further sustainability assessment. Next, the case study includes the environmental assessment (comparative, fast-tracked LCA) and economic assessment (CBA) of the chosen material. The LCA concludes that usage of the bio composite reduces the carbon footprint and energy requirement by 38%; however, increases water consumption by 47%. The result from CBA is that due to the lower weight of bio composite material, an airline can save €3382±338 on 1 out of 18 business class seats during 5 years of aircraft operation; hence, this is by how much ’bio seat’ can be more expensive to be still profitable. Therefore, the case study proves that bio composites might be better than conventional composites from an environmental and economic point of view. The case study presents that sustainability assessment provides information valuable for the decision-making process. Integrating environmental and economic assessment shows a bigger picture and broadens the perspective. Additionally, the analysis of technology based on theoretical frameworks provides important insights for both, decision-making and sustainability assessment. Also, the integration of LCA and CBA tools is concluded to be suitable for this purpose and the methodology is described. The problems associated with such tools combination are discussed, where double-counting is the challenge discovered in the study. In addition, the issues stated in the literature are evaluated, and the propositions on how these challenges can be overcome are indicated.