Accelerating Autonomous Flight: Redefining Low-Altitude Aircraft

EHang’s air taxi
EHang’s two-seat autonomous air taxi conducted a recent unmanned test flight in Raleigh.
Credit: EHang

First there were drones, or unmanned aerial vehicles (UAVs). And then, more grandly, there came unmanned aerial systems (UASs), which encompass the entire package needed to operate a UAV, including the aircraft itself, the ground control station, cameras, navigation sensors, software, training and skills needed, and tools required for maintenance.

UAVs are already a key element serving niches poorly or ill-suited for traditional aircraft. These applications include medical logistics; property and railway infrastructure management; airport, power line, structure and power plant inspections; newsgathering and outdoor videography; forest fire management; and many more. On the near horizon, widespread package delivery and air-taxi businesses will likely expand beyond their current trials in various locations around the world.

Until recently, most civilian UAVs were small (under 55 lb.) devices operated by an individual using a handheld device or cellphone equipped with software to control the drone and capture and transmit images and data to the operator. You can buy recreational drones that meet this definition almost anywhere. Drone clubs are springing up worldwide and evolving into a fascinating, unique competitive genre of its own.

NASAs Grand Challenge illustation
Illustration shows some of the elements involved in NASAs Grand Challenge. Credit: NASA

Meanwhile, businesses and business aviation flight departments are employing more sophisticated hardware for a variety of uses. BCA regularly reports on UAV developments and there are a lot. Indeed, there’s so much activity in this fast-moving topic it can be hard to keep track. With that in mind, this report is intended to help inform those who have not had the time to closely follow the latest advanced air mobility developments on Think of this as a FL 300 overview of the subject.

A New Ecosystem

Enter advanced air mobility (AAM), including the subset of urban air mobility (UAM). While the latter is focused on air-taxi routes and air traffic management within and around cities, AAM will absorb those applications and capabilities and expand beyond the urban complex.

In the last few years, design teams, partnerships and multinational investment deals have radically advanced the AAM concept to encompass piloted and remotely piloted vehicles that are larger, faster and designed with greater range and payloads. AAM supporters are searching intensely for new ways to efficiently move people within and beyond cities in a safe, economical and environmentally friendly manner. Soon, many expect passengers and goods routinely will fly aboard a new breed of smart air vehicles.

By employing novel propulsive systems, airframes, air traffic strategies and governance, these new ventures are likely to compel a redefinition of aviation — including business aviation.

In the accompanying “AAM Developments” sidebar, we take a look at AAM safety, regulatory initiatives, technology and promising applications. But first we’ll look at some of the visions, goals and sober appraisals of AAM.

Great Expectations

There exists a portion of the public that believes on-demand and automated passenger and cargo air transportation services, typically without a pilot, are imminent. And, in fact, some medical and other supplies are now being delivered by UAVs in various parts of the world. But before these activities become commonplace, some major issues must be resolved.

Joby eVTOL
Startup UAV developer Joby has a Defense Innovation Unit contract to study moving supplies around military areas using its eVTOL. Credit: JOBY

Nine out of 10 people live within 30 min. of a small community airport. That fact supports the practicality of using AAM to augmentuser services among community airports in addition to hub airports, thereby facilitating improved air access to commerce, airline travel and urban centers.

Key industry organizations have stepped up to analyze, coordinate and promote AAM development. And while there’s no complete agreement on all the details, there is growing consensus among those involved that the time for AAM is near, perhaps as early as 2023.

Government Promotion

NASA launched the Advanced Air Mobility National Campaign in March. It is intended to take an ecosystemic approach across five to 10 years, looking at all aspects of AAM and how it will be integrated into the nation’s airspace system.

The agency is using the campaign to collect data and allow for testing opportunities for manufacturers and airspace service providers at all levels of maturity and provide the FAA with a clearer picture of how to make AAM a reality. More recently, NASA announced that it would be partnering with more than a dozen companies on the initial National Campaign Developmental Test (NC-DT) event in 2021. Joby Aviation is the only company providing an aircraft for flight testing thus far, but NASA has also partnered with vehicle developers Bell and Boeing, as well as airspace service providers such as AirMap and GE/Airxos.

Ultimately, the goal of the AAM National Campaign (formerly called the UAM Grand Challenge) is to gain public confidence and accelerate the realization of emerging aviation markets for passenger and cargo transportation in urban, suburban, rural and regional environments.

NASA’s vision for AAM is that it:

  • Will provide safe, sustainable, accessible and affordable aviation for transformational local and intraregional missions.
  • Will provide transportation of passengers and cargo as well as aerial work missions, such as infrastructure inspection or search and rescue operations.
  • Will provide services of about a 50-mi. radius in rural or urban areas, as well as missions of up to a few hundred miles to connect urban areas, rural areas, and rural with urban areas.

To help make that vision a reality, the agency will host a series of formal AAM campaigns beginning in 2022. These are designed to:

  • Gain public confidence in AAM safety.
  • Give vehicle manufacturers, operators and airspace service providers insights into the evolving regulatory and operational environment.
  • Facilitate community-wide learning while capturing the public’s imagination.

The AAM National Campaign is intended to bring together aircraft manufacturers and airspace service providers to help identify maturity levels for vehicle performance, safety assurance and airspace interoperability and to develop and demonstrate integrated solutions for civil use.

Working with industry partners, NASA plans to develop testing scenarios that:

  • Address key safety and integration barriers across AAM vehicle and airspace systems.
  • Emphasize critical operational challenges toward commercial viability and public confidence in AAM operations.
  • Identify requirements for AAM system development.

The first formal campaign, NC-1, is to enable participants to demonstrate integrated operations in relevant scenarios that include:

  • Two-way network flight-plan communications.
  • Beyond visual line of sight (BVLOS) operations.
  • Simulated vehicle and operations contingencies.
  • Dynamic traffic avoidance and trajectory management.
  • Approach and landing in the presence of real structures (e.g., buildings in an urban environment) and associated mechanical turbulence.

NC-1 will be based on initial commercial operations proposed by industry for low-density, low-complexity environments. The test will also include key elements required to scale operations for more-complex environments.

Important to the AAM campaign’s success will be NASA’s continued close collaboration with and involvement of the FAA throughout all stages of the effort. NASA plans to address information requirements and provide lessons learned to inform FAA policy decisions on AAM safety, certification, operations and airspace integration.

While the first National Campaign is targeted for 2022, several developmental testing activities are planned to precede that. The first step involves activities — under the NC-DT event at NASA Armstrong Flight Research Center at Edwards AFB, California — that will lay the groundwork for the first challenge.

So far, 17 companies have signed Space Act Agreements with NASA to participate in the NC-DT and activities leading up to the first National Campaign. With these pacts, which do not involve the exchange of funds, both NASA and the signatories are to provide resources to accomplish the goals of the testing.

Roundtable Ruminations

This year, the Aerospace Industries Association (AIA) took part in the Consumer Electronics Show in Las Vegas for the first time. This major gathering of technology companies and experts provided a forum for the association to bring together key U.S. leaders and discuss the future of technology. In partnership with the Consumer Technology Association (CTA), the AIA co-hosted a UAM roundtable.

Elroy Air’s Unmanned Cargo Aircraft
Elroy Air’s Unmanned Cargo Aircraft proposal Credit: Elroy

The AIA-CTA discussion featured a number of top U.S. leaders in this area, including Transportation Secretary Elaine Chao, NASA Associate Administrator for Aeronautics Bob Pearce, Denver Mayor Michael Hancock and Los Angeles Transportation Department General Manager Seleta Reynolds, as well as a number of representatives from companies including EmbraerX, Bell, Uber Elevate, Deloitte and Boeing.

Several key themes emerged at the roundtable that will likely be the focus of subsequent AAM working groups:

  • The vehicle is important, but focus cannot rest solely on it. For AAM to be successful in the long-term, the physical infrastructure, such as vertiports, and digital infrastructure, including user apps, cybersecurity, ATM technology integration and a robust supply chain, must be developed.
  • All actors in the discussion must be included to ensure ongoing dialogue with diverse participants from industry, all levels of government, infrastructure companies, urban planners and others. These conversations will be vital to achieving regulatory approvals, attracting investment, building a supply chain, attracting early users, addressing safety and environmental concerns, and garnering broad public acceptance.

Market Study

An October 2018 UAM market study by Booz Allen Hamilton, an American management and information technology firm, concluded that in 10 target U.S. urban areas, airport air-shuttle and air-taxi UAM operations would be viable, and under the best-case scenario have a market potential of $500 billion. Further, it determined that so-called hybrid vertical-takeoff-and-landing (VTOL) aircraft with one pilot on board and automation serving as a backup could serve the air-ambulance market successfully.

The study also found constraints could be addressed with intragovernmental partnerships such as NASA/FAA, government/industry collaboration and existing legal and regulatory enablers. It employs the NASA definition of UAM “as a safe and efficient system for air passenger and cargo transportation within an urban area, inclusive of small package delivery and other urban UAS services, that supports a mix of onboard/ground-piloted and increasingly autonomous operations.”

The report details some of the technological constraints seen in the near-term immature market, including:

  • The high cost of the service, partially driven by capital and battery costs.
  • Adverse weather.
  • ATM systemic stresses.
  • The limitations of current battery technology, particularly in an electric vertical-takeoff-and-landing (eVTOL) air ambulance scenario.
  • Other impacts, including community acceptance of eVTOL noise.

In a longer-term mature market, Booz Allen Hamilton analysts see the following tech challenges:

  • Energy and environmental impacts of large-scale operations.
  • Cybersecurity of autonomous
  • systems.
  • Significant weather impact on large-scale operations.
  • Large operations of new entrants, commercial space operations and private ownership of UAM vehicles could increase the complexity of airspace management and safety.

Non-technological issues seen in short- and/or long-term scenarios include:

  • Competition from emerging technologies and concepts like shared electric and autonomous cars, and fast trains.
  • Social mobility: new importance of travel time, increase in telecommuting, urbanization and de-congestion scenarios could reduce the viability of markets.
  • Preference to fly with others they know in an autonomous UAM.
  • Public perception: passengers’ trust and apprehension with automation and pilotless UAM.
  • Increase in some adverse weather conditions due to climate change may limit operations.
  • Competition from existing modes of transportation.
  • Public perception: passengers’ concern about safety, security screening and preference for UAM only for longer trips.
  • Laws and regulations for flying over people, BVLOS and carrying passengers (among others) are needed.
  • Certification: gaps in the existing certification framework where UAM will experience challenges, particularly system redundancy and failure management.

Another Study

In a Stanford University publication, Strategies for Posing a Well-Defined Problem for Urban Air Mobility Vehicles 2019, researchers pointed out that American cities dominate the top-10 list of the most-congested cities around the world: Los Angeles (first), New York (third), San Francisco (fourth), Atlanta (eighth) and Miami (10th). This problem is expected to be exacerbated by growing populations and rising urbanization over the coming decades. In many states, there simply is no more physical space to build new transportation infrastructure.

“One offered solution is a data-driven approach to balance transportation network supply and demand,” the authors state. “Another . . . is the utilization of the three-dimensional airspace to alleviate vehicle congestion on the ground. Capable of taking off, hovering and landing vertically, eVTOL aircraft have the potential to address some of the major shortcomings of present and future urban mobility.”

Agility Prime

The U.S. Air Force is expanding its interest in emerging eVTOL aircraft, in late February releasing its first “innovative capabilities opening” under the new Agility Prime program, for vehicles able to carry up to eight people. Two additional “areas of interest” (AOI) were announced on April 28, for vehicles up to two people or more than 500 lb. of cargo.

AOI 1 is looking at vehicles able to carry three to eight people over a range greater than 100 mi. at a speed greater than 100 mph. This covers most of the eVTOL air taxis now in commercial development, such as the Joby Aviation Generation 2 tilt-prop now in flight testing.

Due to the COVID-19 pandemic, the Agility Prime launch event, scheduled to be held in Austin, Texas, in late April, was transformed into a virtual online event during the week of April 27. Hayward, California-based startup Sabrewing Aircraft’s Rhaegal-A was rolled out virtually on May 1, at the close of the kickoff event.

The Air Force also is interested in smaller eVTOLs carrying up to two people and being developed under FAR Part 103 rules for ultralight aircraft, says Col. Nate Diller, Agility Prime team lead and director of the Air Force’s AFWERX innovation unit. Examples include the LIFT Aircraft Hexa and Opener BlackFly.

Agility Prime is also interested in hybrid eVTOL unmanned cargo aircraft for longer-range logistics missions. Examples include the Elroy Air Chaparral now in flight testing and the Sabrewing Rhaegal.

AOI 1 requires bidders to fly their aircraft by Dec. 17 of this year. Joby and Beta Technologies are the first eVTOL developers to advance to the third stage of Agility Prime and receive contracts to provide flight simulators and test data.

The final product of AOI 1 will be prototype test reports that show which companies involved have a technical solution and have reduced technical risks through testing, Diller said. Then there could be follow-on contracts for operational testing and potentially procurement for an early operational capability.

The Air Force is aiming to field an initial handful of eVTOL vehicles for logistics missions by 2023, the current date for initial commercial UAM services targeted by the Uber Elevate aerial-sharing initiative. “We want to leverage those companies that are looking to be FAA-certified and in production by that time,” Diller said. To support the effort, the Air Force is offering its test ranges, considerable engineering talent and certification experience.

Agility Prime has also awarded Small Business Innovation Research (SBIR) contracts to Sabrewing Aircraft and Elroy Air worth a few million dollars each. But since the vast majority of funding for urban air mobility startups has come from the private sector, the coronavirus pandemic has disrupted fundraising activities worldwide.

Another Initiative

The NBAA is one of the founding members of a new organization — the Community Air Mobility Initiative (CAMI) — dedicated to providing communities and policy makers with the information and tools that will be vital to the successful integration of urban air mobility aircraft into daily transportation options.

“The NBAA is a strong proponent of UAM and eVTOL, as there’s a clear connection to this technology for business aviation — whether it’s transporting employees within or between cities, or connecting transportation centers with local businesses,” said Mike Nichols, NBAA senior vice president of strategy and innovation. “We have a great infrastructure in place with our regional representatives and regional business aviation groups to advocate in support of UAM and we look forward to working with CAMI to achieve this.”

CAMI’s mission is to support the responsible integration of urban air mobility into communities through education, communication and advocacy. It connects communities and industry by providing resources to the public and decision makers at the state and local level.

“New technologies and new aircraft promise to make flight accessible and practical on a daily basis for more people than ever before,” said CAMI Co-Executive Director Anna Dietrich. “With that promise comes the responsibility to integrate those aircraft into our communities safely, responsibly and equitably. We created CAMI as the industry’s commitment to our neighbors and the decision makers who support them to work to ensure that happens.”

The NBAA’s support for UAM was evident at its annual convention last fall, which featured, for the first time, an exhibit area for UAM aircraft, many education sessions about this emerging technology and the release of a report, co-authored by the NBAA and NEXA Advisors, detailing the financial and business case for UAM.

In addition to the NBAA, founding CAMI members include:

  • Bell.
  • Black & Veatch.
  • Choctaw Nation of Oklahoma.
  • General Aviation Manufacturers Association (GAMA).
  • Joby Aviation.
  • Jump Aero.
  • Karem Aircraft.
  • Massachusetts Department of Transportation.
  • Raytheon.
  • SAE International.
  • Unmanned Safety Institute.
  • Vertical Flight Society.

UAM to the North

With partners across government, academia, industry and the investing community, the Canadian Air Mobility Consortium plans to lay the foundation for advanced air mobility across the nation, including drone delivery and passenger/cargo air taxis, with an emphasis on sustainability offered by electric aircraft.

Matching closely with NASA’s roadmap for technological development and deployment, the group is raising $1 million from partners — with a 50-50 match from Canadian federal, provincial and local governments — to conduct an economic analysis, develop operational and scenario applications, and then hold a demonstration event originally intended for 2020, although that may slip into 2021 due to the coronavirus pandemic.


Clearly, obstacles remain to be cleared. Launching some of the proposed ventures will likely cost millions, even billions of dollars before showing a profit. In the ongoing pandemic, funding is likely to be uncertain. Certification, automation, airspace integration, human-machine interaction, cybersecurity, noise, hiring engineering talent and allaying public concerns about sharing dense urban airspace with flying robots will take time, likely more than the participants in the aforementioned AAM studies, organizations and developers foresee.

For AAM to succeed, it cannot focus on one-off operations, but rather on how these operations will reach scale. Safety is paramount and the activity must be unobtrusive. Once those are assured, the public may be able to see the benefits, including connecting people and goods between, to and within cities and beyond in ways that were never before possible. It’s noteworthy that mature organizations like NASA, the U.S. Air Force and the AIA are vetting and marshaling the players and gently guiding the emerging sector.

A successful AAM industry requires the integration of aviation into existing urban and regional transportation systems that are currently fraught with their own challenges, including traffic congestion, urban sprawl, environmental impacts and noise.

Although its challenges are formidable, AAM offers the potential to not only change the way in which people commute, but also open new markets for cities, industries and their workforces. By looking at the transportation ecosystem as a whole and including all actors from across industry and government in the discussion, a revolution and tremendous expansion in aviation could result.