Urban Air Mobility (UAM) is an emerging concept envisioning a safe, efficient, accessible, quiet, and multi-use air transportation for passenger mobility, cargo delivery, and emergency management within or traversing a metropolitan area. Urban air mobility is part of the U.S. Department of Transportation’s broader vision for Mobility on Demand (MOD), an innovative transportation concept evolving around connected travelers, where consumers can access mobility and goods delivery services on demand by dispatching or using urban aviation services, courier services, shared automated vehicles, shared mobility, public transportation, and other innovative and emerging transportation technologies. In recent years, several companies have designed and tested enabling elements of the UAM concept including; prototypes of vertical take-off and landing (VTOL) capable aircraft, operational concepts, and market studies to understand potential business models. While UAM may be enabled by the convergence of several factors, several challenges such as: community acceptance, safety, equity, issues around planning and implementation, airspace, and operations, could create barriers to mainstreaming.