Urban Air Mobility (UAM, also known as advanced air mobility) is an emerging concept that envisions a safe, sustainable, affordable, and accessible air transportation system for emergency management, cargo delivery, and passenger mobility within or traversing a metropolitan area. While numerous societal concerns have been raised about these approaches (e.g., privacy, safety, security, social equity), on-demand aviation has the potential to provide options for emergency services, goods delivery, and passenger mobility in urban and rural areas using small piloted and autonomous aircraft. This chapter provides a short overview of developments in on-demand aviation and a discussion of the potential impacts and challenges of UAM on communities. Potential challenges include safety, financial, and community acceptance, among others. Research that seeks to understand the potential societal barriers can help to identify challenges and mitigate potential UAM concerns. Research on the potential impacts of UAM, coupled with thoughtful planning and implementation, are needed to balance commercial interests, technology innovation, and the public good.