Urban Air Mobility-defined as safe and efficient air traffic operations in a metropolitan area for manned aircraft and unmanned aircraft systems-is being researched and developed by industry, academia, and government. Significant resources have been invested toward cultivating an ecosystem for Urban Air Mobility that includes manufacturers of electric vertical takeoff and landing aircraft, builders of takeoff and landing areas, and researchers of the airspace integration concepts, technologies, and procedures needed to conduct Urban Air Mobility operations safely and efficiently alongside other airspace users. This paper provides high-level descriptions of both emergent and early expanded operational concepts for Urban Air Mobility that NASA is developing. The scope of this work is defined in terms of missions, aircraft, airspace, and hazards. Past and current Urban Air Mobility operations are also reviewed, and the considerations for the data exchange architecture and communication, navigation, and surveillance requirements are also discussed. This paper will serve as a starting point to develop a framework for NASA's Urban Air Mobility airspace integration research and development efforts with partners and stakeholders that could include fast-time simulations, human-in-the-loop simulations, and flight demonstrations.A https://ntrs.nasa.gov/search.jsp?R=20180005218 2020-07-07T23:11:55+00:00Z of ODM that is focused on air traffic operations in metropolitan areas with aircraft capable of seating a small number of passengers or equivalent volume of goods flying trips of about 100 nautical miles (nmi) or less.The technologies and procedures required for ODM were investigated in a NASA study [14] that covered the range of the airspace integration problem, including mission planning, separation from hazards (e.g., terrain, obstacles, other aircraft), contingency management, demand-capacity balancing, traffic flow management, as well as sequencing, scheduling, and spacing. A similar spectrum of topics will be covered in this complementary paper on UAM airspace integration. This paper also describes at a high level NASA's initial airspace integration concepts for both emergent and early expanded UAM operations. It also serves as a framework for NASA's UAM airspace integration research and development efforts with partners and stakeholders.The remainder of this paper is organized as follows. Section II reviews past and current UAM operations. Section III presents an overview of UAM, including the goals, principles, barriers, and benefits. This section also discusses the competing considerations that need to be taken into account and balanced for UAM operations, as well as the requirements for communication, navigation, and surveillance. Section IV defines the scope of the concepts with regard to missions, aircraft, airspace, and hazards. Section V describes at a high level NASA's initial airspace integration concepts for both emergent and early expanded UAM operations. Section VI discusses NASA's plan to develop and refi...