Contents I. Introduction
The demand for passenger and goods transportation has increased considerably in recent decades, even more so in urban areas. To keep up with the ever-increasing demand, an expansion of the transportation infrastructure has been taking place in the form of new roadway construction, the addition of buses, trams, and subway trains, creation of intermodal and multimodal transport hubs, and so on. Despite these efforts, ground-based transportation systems are nearing or exceeding capacity. To expand urban transportation system capacity, the third and arguably the least utilized spatial dimension, low altitude airspace, has begun to receive increasing attention from various transportation stakeholders. Recent technological advances and substantial investments have paved the way toward the conceptualization and development of a new urban transportation mode, popularly referred to as urban air mobility (UAM), which seeks to utilize a low-altitude flying scheme for transporting passengers and goods within urban environments, (urban and suburban areas within a single metropolitan area). Due to the operational characteristics of UAM, it is considered a disruptive transportation technology that brings the possibility of lowering travel time, and increasing travel time reliability in dense, congested urban settings. In addition, UAM offers considerable potential for enhancing emergency response, critical medical services, and disaster relief operations.
