Multi-Dimensional Evaluation of Urban Air Mobility of eVTOL Airspace Configurations to Optimize Operational Risk, Efficiency, and Capacity

Urban Air Mobility (UAM) is expected to enable high-density low-altitude operations of electric vertical take-off and landing (eVTOL) aircraft, but the associated risks depend strongly on the chosen urban airspace structure. This study applies an integrated Analytic Hierarchy Process (AHP). Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) approach to evaluate six airspace structure alternatives (Full Mix, Tubes, Zones, Layers, Corridors, and Skylanes) against nine risk-relevant criteria: operational risk (C1), security (C2), third-party risk (C3), time and energy efficiency (C4), social impact (C5), operating range (C6), accuracy requirements (C7), airspace utilization (C8), and airspace capacity (C9). AHP results show acceptable consistency (CR = 0.096) and indicate that accuracy requirements (w = 0.235) are the most influential criterion, followed by third-party risk (w = 0.173) and security (w = 0.157). TOPSIS ranking identifies layered airspace as the lowest-risk option (closeness coefficient = 0.433), followed by full-mix (0.188), skylanes (0.151), corridors (0.125), tubes (0.052), and zones (0.051). The findings suggest that structured airspace, particularly layered designs, provides stronger risk controllability for early-stage UAM deployment, while more flexible concepts require higher capability in navigation accuracy, monitoring, and enforcement to achieve comparable safety performance