The demand for air transportation service using Urban Air Mobility (UAM) is expected to increase in the future saving travel times in urban areas. An adequate set of services for airspace network management supporting their operations will be then needed. Despite the numerous emerging topics of UAM being widely researched, an analysis of this need is yet to be explored. A multitude of stakeholders involved in the novel UAM industry are studying different airspace management concepts. These concepts are designed with different perspective and background, and tailored to individual goals and needs with no universal way of comparing them. Thus, building a performance comparison framework based on common metrics becomes essential for evaluating such concepts on a quantitative and qualitative level, independently of the country or company of operation. This paper provides a unified method for comparing, evaluating, and assessing different network designs and management concepts for UAM operations based on UAM-tailored metrics. Inspiration for suitable metrics can be drawn from common transportation means that are constantly in use such as commercial air, road, and rail transportation. A subset of key performance indicators from those three domains are considered suitable for UAM, as this emerging means of transportation has some similarities to them. Within this paper, three newly developed airspace management concepts and their applications to two different urban areas are presented first. Then, considering the applicability of existing benchmarks from the three other industries to UAM, a non-exhaustive, yet detailed list of metrics is provided to cover network, vertiport, safety, and human- centered aspects. For the initial investigation, only network-specific metrics are further analyzed and elaborated in this paper.
