The paper deals with the possibilities of reducing aerodynamic drag and modifying airflow in the rear of a hatchback vehicle. This body type is characterised by the formation of turbulent flow behind the vehicle, which has a significant effect on the fouling of the tailgate, including the window. By modifying the geometry of components such as the roof spoiler and additional aerodynamic finlets on the sides of the rear window, the airflow is optimised to reduce aerodynamic drag and thus fuel consumption. Three spoiler designs are proposed, one of which is processed to prototype quality using CAD tools. The body of the vehicle with this design is subjected to CFD analysis and evaluated in terms of the given criteria. The results of the simulations are compared with a model of a production vehicle and a sports version vehicle to assess the effect of the geometry on the flow parameters.