Sweden has an ambitious goal that the country will be carbon neutral by 2045, where this includes all sectors, including transportation and thus aviation. The aviation sector is an important part of the transportationsystem where the development of society has become dependent on this transportationalternative. In 2017, the aviation accounted for six percentof Sweden’s carbon dioxide emissions, one percentfrom domestic flightsand five percentfrom international flights. In order toreduce these emissions, active work is ongoing for a transition where domestic aviation will be fossil-free in 2030 and all departures from Sweden to the international market will be fossil-free in 2045. Aviation has historically had a strong connection to fossil fuels and environmentally friendly alternatives have not yet managed to compete in the market.This study has investigated how sustainability can be a central part of the business model and how these should be adapted as part of the work to a fossil-free business, as well as the role of sustainable aviation fuels (SAF) and policy instruments in the energy transition. By mapping important aspects for sustainable business models, market potential for SAFand the development of new policy instruments,this study contributes with a systems perspective on the Swedish aviation industry's energy transition. The delimitationofthe study has been the Swedish market with focus on actors with their operations in Sweden. The methodologyhas consisted of a literature study, an interview study with 11 actors in the Swedish market and a case study on the airline corporationBraathens Regional Airlines (BRA), which mainly operates domestic flights in Sweden with Bromma as their headquarters.The results showed that there are three areas that are important in the work with sustainable business models, three areas for the market potential for biofuels and four areas for policy instruments. In the development of sustainable business models, cooperation and co-financing are seen as central aspects for an effective transition with better risk distribution. Transparent sustainability work, climate calculations and biofueltickets are considered important tools to increase the customer's understanding of the company's transition towards a sustainable future. The public's lack of knowledge regarding the energy transition for aviation is considered an obstacle towards increased sales of biofuel tickets, which also creates flygskam and avoidance of aviation as a means of transportation. The biggest obstacle towards an increased share ofSAFon the Swedish marketis mainly considered to be the lack of Swedish production.Increased production would mean large investment costs and high risks, which means that co-financed projects are proposed to overcome this obstacle. Biomass as a raw material and how it is used and classified in the EU is also an obstacle towards increased use. Current policy instruments show that the reduction obligation is a positive addition, but the penalty fee needs to be raised above the price of SAF.The EU taxonomy can also play a decisiverole in the transitionprocess, as the classification of biomass and bioenergy can affect interest and willingness to make new investments.In addition, travel policies of companies are an obstacle when they prohibit travel by aviation.Finally, policy instruments are needed that favor Swedish production of SAF, where the industry sees great opportunities in both technology and raw materials, but lack of political initiatives.