The aviation industry keeps evolving and responding to the needs of urban mobility; a promising solution for efficient transportation is electric Vertical Take-Off and Landing (eVTOL) aircraft. In this thesis, a comprehensive methodology for estimating the operating costs of eVTOL aircraft is described, discussing the various cost analysis methods and ultimately selecting the Roskam model as the most appropriate framework for this analysis. This study examines several scenarios in order to define the mission profile, in this case, the journey from Brussels to Liège, which covers a distance of 93 kilometers is selected. In the first stage, the research considers different methods of cost estimation, evaluating their relevance and accuracy in eVTOL operations.