Technological advances in electric propulsion and control systems, computer systems, sensors, precision position and navigation information, and other areas are facilitating the development and operation of new air vehicles potentially capable of safe, reliable, and low-noise flight, including vertical flight, with simplified vehicle operations or autonomy and with lower operating and maintenance costs than conventional aerial mobility. This transformation, which this committee refers to as advanced aerial mobility, is leading to an expansion of the potential opportunities where flight is utilized to accomplish tasks in industries across the economy and in ways that have the potential to be safe, environmentally responsible, and acceptable to the community. While in its infancy today, advanced aerial mobility has the potential to bring profound changes across passenger transport, cargo logistics, deliveries, and business and consumer services, in addition to broad second-order effects across these industries.
Advanced aerial mobility includes manned and unmanned, autonomous and pilot-supervised aircraft of any size and mission operating safely and responsibly in an integrated National Airspace System. These can include both electric and hybrid aircraft. The term applies less to specific aircraft than to the overall method of operations and purpose. By responsibly, the committee believes that participants of the integrated National Airspace System must meet high standards in terms of the overall integrity of the vehicle, its navigation system, and its adherence to assigned path and airspace. The diverse set of envisioned advanced aerial mobility operations range from commercial transport and air taxi services to drone surveillance and inspection in urban to rural regions (see Figure 1.1).
The committee’s statement of task is to lay out a national vision for advanced aerial mobility and research recommendations that overcome the technical, regulatory, and policy barriers that sit between today and achieving the vision. Even in these early days, the dynamism in this space across vehicle development, new mission profiles, emerging applications, infrastructure requirements, and airspace system management makes this a challengingly broad topic to cover comprehensively. Yet, the criticality of charting out a national vision for advanced aerial mobility at this time cannot be understated.
The path to the routine acceptance of a new, disruptive transportation ecosystem is daunting. Challenges abound, as the global airspace in its present form was not designed to accommodate the levels of autonomy needed to make advanced aerial mobility scalable and thus a viable option. Success of advanced aerial mobility systems
will be dependent on several factors if they are to be accepted from an economic, social, and regulatory standpoint. Some of these factors are as follows:
- Safety. Advanced aerial mobility will have to demonstrate the high safety levels expected by the public for modern air transportation systems.
- Security. Emerging technologies present new cybersecurity risks and vulnerabilities that will have to be managed.
- Social acceptance. New products or services applying advanced aerial mobility must gain the trust and support of the public, taking into account multiple factors.
- Resilience. Contingency management, the ability to manage the expected and the capability to recover from the unexpected, will be a key to success.
- Environmental impacts. Factors such as noise and visual impact from air vehicles on the environment and nonparticipants will have to be minimized to acceptable levels.
- Regulation. New rules to accommodate the technology as well as to define its integration into the National Airspace System will have to be created.
- Scalability. Any successful approach to advanced aerial mobility will need the capability to scale as market segments emerge and grow.
- Flexibility. With any disruptive new initiative, flexibility is critical as new use cases and operational concepts emerge.
A key application area for new capabilities in flight is urban air mobility (UAM), air passenger and cargo transportation within or to/from a metropolitan area with vehicles ranging from small drones to passenger aircraft, including in some cases electrically powered vertical takeoff and landing capabilities. Although “urban air mobility” is the current, commonly accepted term, the committee considers UAM to be a subset of the overall subject, albeit the most challenging one. UAM presents an illustrative case study with respect to the factors enumerated above. For UAM to thrive, it must achieve large scale and therefore must gain public support and acceptance by society through demonstrating all of the other factors. In fact, if it fails to achieve large scale, it risks growing barriers from a societal acceptance standpoint (see Figure 1.2).
Four general areas need to be addressed:
- Technology. Technological advances will be needed to scale what exists today. These advances include acoustics and noise reduction, autonomy and software capabilities, ways to design safety into the system and to convince the users that risk is acceptable, and efficiency to overcome cost barriers.
- Operations. The public will not accept greatly increased flight operations over their homes and in their “airspace” unless noise and obtrusiveness, and the resultant effects on family and community life, can be minimized. Safe interoperability with all other aircraft in both controlled and uncontrolled airspace classes must be assured.
- Safety and privacy. The success of traditional transport systems has hinged on the ability of the industry to convince the public about its safety. Whether or not the fears are rational, success of advanced aerial mobility will require a very high safety record. The potential impact of advanced aerial mobility on privacy and security will need to be at publicly acceptable levels.
- Public relations. A public relations campaign will be necessary to overcome any natural fears or misunderstandings and to build trust in these new systems. This campaign will have to include purposeful public messaging, education, and case studies and demonstrations of benefits. Enlisting the public as stakeholders and advisors can also be effective. Part of the messaging and case studies will likely be services provided by other parts of advanced aerial mobility that will have the greatest impact and attraction by the public, such as first responders, disaster relief, crime reduction, and firefighting.1
Many of the early advances in aerial mobility are currently and will in the near future be made in nonurban areas, which are not as congested and have lower population densities. As the committee notes later in this report, introducing new forms of air transportation inside or outside of urban areas could have considerable community impacts involving safety, privacy, and environmental factors. Ultimately, the widespread adoption and success of advanced aerial mobility depends on understanding and mitigating these impacts, so that the desired public outcomes are designed into the system.
At this time, several government agencies have some responsibilities for overcoming challenges of large-scale advanced aerial mobility operation, but there are important gaps that need to be filled where the responsibilities should be assigned and coordination will be important in some areas. As can be seen in Figure 1.3, there are currently three areas of gaps or unmet needs for the private sector:
- A mandate must be created within the public sector to deliver progress toward enhanced capabilities for the National Airspace System that enabled advanced aerial mobility, increasing automation and the emerging applications of flight it enables. This is not currently the responsibility of the Federal Aviation Administration (FAA), the National Aeronautics and Space Administration (NASA), or industry. Progress will require mobilizing the private sector, expanding and growing aviation applications, and overall leadership to promote advanced aerial mobility in the United States.
- Various capabilities within the public sector are required to successfully achieve the goals of an advanced aerial mobility vision, but these exist currently only at varying levels. Required capabilities include system engineering, industry-government interfaces, necessary standards, program management, public-private partnerships, systems delivery, and certification.
- Authority needs to be in place for making decisions about advanced aerial mobility system-wide architectures, concept and systems definition, and rulemaking.
There is a need for an assigned overarching entity that is chartered with coordinating the necessary stakeholders and establishing an advanced aerial mobility system along some pre-stated goals. Without such coordination at the federal government level, the progress will be hindered as well-intentioned local ordinances create varying requirements that will be impossible to collectively meet.
1 See National Academies of Sciences, Engineering, and Medicine, 2018, Assessing the Risks of Integrating Unmanned Aircraft Systems Into the National Airspace System, The National Academies Press, Washington, D.C., https://doi.org/10.17226/25143.
Private industry is working to close some of these gaps. But without an assigned government agency responsible for these areas, advanced aerial mobility could be impeded or fail to reach even a portion of its potential.
Adopting advanced aerial mobility in the United States is in the national interest, as is maintaining U.S. leadership in aerospace. A vision, and a way to achieve it, is crucial if the United States is to realize this goal. Beyond technical hurdles and system engineering, advanced aerial mobility will require addressing societal acceptance and policy issues related to privacy concerns, community preferences, airspace allocation, and land use considerations. Given the complex interdisciplinary nature of advanced aerial mobility and the gatekeeping role of regulation, planning and coordination for advanced aerial mobility has to take place at the federal level, with the aim of delivering the foundational decisions, standards, and regulations that enable the private sector to invest and deliver its innovations with clarity and confidence.
The long-term impacts of advanced aerial mobility on the economy and society could bring wide-ranging substantial benefits. The purpose of this study is to lay out that vision and is but a first small step that others will have to expand and build upon.
The vision for an expanded role of flight in society and the economy is not a new one but rather a longstanding goal from the early days of aviation—one hindered by the limitations of 20th century technology. In fact, from the day in 1927 that Charles Lindbergh landed the Spirit of St. Louis at Le Bourget in Paris, people have envisioned the potential of personalized flight to support on-demand movements of passengers and goods directly between locations.
At the time, Charles Lindbergh’s crossing of the Atlantic was a pivotal moment, bringing a wave of capital, entrepreneurs, and engineers into the industry. Similar to today, a wave of innovation catalyzed many new businesses. Their shared vision was that soon everyone would be flying in aircraft at their own whim akin to using a car.
Aviation has come a long way since then, connecting the world, yet that vision has remained elusive. For nearly a century, flying for most people has been constrained to aggregation of passengers on long-distance, scheduled commercial air routes, with only enthusiasts or the wealthy undertaking the expense and complexities of private aviation.
This outcome was not expected. Progress during World War II raised expectations for a domestic revolution in the use of personal airplanes. Wartime advances in aircraft design and manufacturing, combined with the large number of trained pilots and people otherwise exposed to flight, fueled expectation that following the war there would be demand for hundreds of thousands of airplanes as the economy transitioned to peacetime growth. Indeed, industry responded, with manufacturers preparing themselves and the public for the coming new era in flight.
According to the General Aviation Manufacturer’s Association, the general aviation industry sold a record high 33,254 aircraft in 1946, many of which were surplus World War II aircraft; however, the initial success did not last long. A contraction in aircraft sales came about suddenly thereafter. In 1947, aircraft sales dropped by half and declined further into the early 1950s. After a recovery in the 1960s and 1970s, general aviation aircraft shipments stalled again in the wake of product liability costs (see Figure 1.4).
Historical aircraft shipment data support the observation that general aviation failed to scale. The reasons behind this are numerous and interdependent. Operating small combustion-powered aircraft proved to be too expensive, and their complexity and consequent maintenance made them costly and unreliable. At the same time, piloting aircraft remained complex, with steep training requirements that held back growth in the pilot population. These forces limited scale and innovation and combined to keep aviation for personal transport beyond the reach of mass adoption. Ultimately, 20th century technology was not able to support a product that could scale into the needs of the personal aviation market (see Figure 1.5).
In contrast, commercial aviation thrived. Here, efficiencies could be gained through larger aircraft and complexity managed with highly trained professional pilots. Early regulated air service transitioned through deregulation and route structure and business model innovation. Today, as tens of thousands of people pass through mega-hub airports daily, one might wonder if personal aviation was a misguided idea or just before its time.
As discussed earlier in Chapter 1, technological advances in software and data, electric propulsion, sensors, and other areas are now spurring an entire industry to revisit this question. Technology is redefining flight, with software and data as critical elements of the advancements at hand. As firms apply these technologies to aircraft and the overall airspace system, they upend core assumptions around the aircraft, its economics, safety, usability, and the transportation systems in which it will operate.
At present, the United States is potentially on the cusp of a revolution in transportation with long-term, far-reaching implications, from how people get across town to how to connect broader regions and move goods or provide essential services. The new capabilities that advanced aerial mobility delivers can significantly broaden the application of flight to drive productivity across the economy.
To understand the impact that truly accessible flight capability can have, it is helpful to understand that advanced aerial mobility represents the inclusion into this transportation mix of a mode that stands apart from
today’s infrastructure intensive networks. Aerial mobility is a nodal transportation network in contrast to road and rail, which are linear networks. The flexibility, resilience, and low resource intensity of nodal networks are key strengths and, as evidenced by water transport throughout history, have proven value (see Figure 1.6).
As advanced aerial mobility matures and is deployed, each application has the potential to bring profound impact, because it represents the inclusion into the transportation mix of a nodal network—a transportation mode that is not limited to linear physical path infrastructure (e.g., roads and rails) and that does not depend on building and maintaining extensive infrastructure to sustain or expand service capacity over time.
The current commercial air transport system is a nodal network; however, an advanced aerial mobility network will have some differences. Such a network is a more complex and multidimensional space than the current air traffic system, which has legacy attributes of static routes. At its most basic form, it includes many more nodes, not all of which are fixed (e.g., drones taking off and landing on delivery trucks). It is inherently far more complex when displayed visually but can have many advantageous attributes, such as flexible capacity and resilience to disruption, among others. While the advantages to a nodal network are clear, it must be recognized that the nature of airspace management may require a level of flexibility to route structure based on variables such as weather, security concerns, and other stakeholder activity in the airspace volume. Further, as megacities scale, their area increases—providing a fundamental challenge to linear, path-based networks.
In contrast, major transportation networks such as roads and rail are linear. They must be built and maintained. Routes are fixed and limited in capacity. They make a permanent imprint on the landscape, influencing future behavior for centuries. In linear networks, a single vehicle can cause congestion, and these effects can ripple through the networks (see Figure 1.7).
Today, the nodal networks of ocean transport and commercial air travel serve only narrow use cases within the overall transportation systems. The modern world runs primarily on roads and rail, particularly for short to medium journeys.
The consequences of modern society’s transportation dependence on linear networks are growing ever more apparent. Megacity regions push the limits of road scale and congestion. Infrastructure becomes costlier to maintain with age. In the United States, infrastructure is deteriorating yet combined spending to maintain road networks
exceeds $145 billion annually.2 Increased roadway congestion results in billions of dollars of lost productivity, and ongoing maintenance costs inhibit road expansion, particularly in dense urban areas. In contrast, the $4.1 billion runways and related airfield infrastructure (excluding terminal and amenities) cost of air transportation is indicative of its high efficiency.
Advanced aerial mobility development will evolve in response to technical, regulatory, and economic factors, generally taking the path of overall least resistance as the private and public sectors work in their respective roles to facilitate progress. Where it is found to be feasible and economically attractive, innovators can create a lightweight transportation capability that delivers benefits quickly and effectively introduces a thin overlay of high-speed flexible transport, complementing existing linear networks. These early applications become the seeds of a modern nodal network. With this, the community builds experience in overcoming the technical, regulatory, and societal hurdles required for future larger-scale implementation.
A nodal aerial transportation network represents a fundamental step forward for transportation and society. As a complement to linear networks, it allows separation of high-priority movements such as medical emergencies and disaster relief onto a resilient high-speed network not subject to disruption on the ground. With operating experience, the scale and use cases expand dramatically.
It is very difficult to define how new capabilities in flight will be put to use ex ante. A fundamentally new capability in flight implies an expansion of creative uses to drive productivity across the broader economy. Within advanced aerial mobility, the potential uses, configurations, and operating models are numerous and highly diverse. In setting a path toward a national vision for advanced aerial mobility, acceptance of this fact is important. Any vision must first address safety, but it must also accommodate scale, mitigate potential impacts, and build in flexibility to enable new and unforeseen applications to unfold.
Pursuing this vision to establish and maintain U.S. leadership in this new capability is in the national interest. However, aerial mobility systems will not self-assemble out of the private sector. Both private and federal investment in research and development supporting the development of standards and regulations throughout the aerospace ecosystem will play an important role.
2 U.S. Department of Transportation, Bureau of Transportation Statistics, 2017.