and policing services (Reiche et al., 2019). The aviation industry needs to address the technological, physical, functional, and integrational challenges of system-of-systems depending on each other to a large degree to make UAM viable (NASA, 2018). Many of the most critical problems to UAM are the capacity of the existing air traffic management system, the accessibility of takeoff and landing areas and charging systems on the ground, regulations and certifications, adverse weather conditions, pilot shortage, and public acceptance of aircraft noise (Vascik & Hansman, 2018). These challenges could hinder implementation and limit the sustainable growth of UAM systems. To tackle these challenges, many organizations in the aviation industry, academia, and government have conducted extensive studies on the issue of UAM vehicle development and technology. The National Aeronautics and Space Administration (NASA) has carried out numerous ongoing research projects that substantially support UAM. These continuing projects include "UAS Traffic Management (UTM) & UAS Integration in the NAS (UAS-NAS), Flight Demonstrations and Capabilities (FDC), X-57, Air Traffic Management-Exploration (ATM-X), System Wide Safety (SWS), Transformative Tools & Technologies (TTT), Revolutionary Vertical Lift Technologies (RVLT), and Advanced Air Mobility (AAM)" (NASA, 2019, p. 11). UAS are currently operating at low altitudes (e.g., below 400 feet). UAS have used the Unmanned Aircraft Systems (UAS) Traffic Management (UTM) services, which provides a set of traffic management services via a federated group of UTM Service Suppliers (USS), similar to traditional Air Traffic Control (ATC) services provided to IFR and VFR aircraft (Lascara et al., 2019). According to Ghayouraneh, El-Ghazaly, and Rankin (2018), UAM operations are expected to occur above 400 feet (between 1,000-3,000 feet). Even when transitioning from higher airspace to lower airspace (below 400 feet), UAM aircraft may not be able to leverage 58