Urban Air Mobility (UAM) is an emerging field which can revolutionize regional transport in the near future. KoriAir project aims to design a vehicle which is more efficient and quieter than current vehicles. This report presents the preliminary design solving those challenges. The resulting design is a two-vehicle configuration consisting of a lifting vehicle and a cruise vehicle. The lifting vehicle is a multicopter with vertical take-off and landing capabilities. The cruise vehicle design is based on a general aviation aircraft. After take-off, the coupled vehicles decouple, allowing the cruise vehicle to continue its mission before it couples in-air for landing. The report presents the preliminary design of two vehicles. In addition to that, a coupling mechanism with its control system is designed. To integrate well in the urban environment, noise generated by the vehicles is addressed. Infrastructural and operational aspects are also considered, with details about vertiport design and route planning presented.