In August 2001, an anonymous guest posted on the forum at Airliners.net, a popular aviation website. “How Long Will Pilots Be Needed?” they wondered, observing that “20 years or so down the road” technology could be so advanced that planes would fly themselves. “So would it really be useful for a person to go to college now and be an airline pilot if a few years down the road they will be phased out by technology?”
Twenty-four years later, the basic technology required to make aircraft fly themselves exists, as evidenced by the fact that most commercial flights are flown largely on autopilot. Yet, the fundamental model of flying commercial aircraft hasn’t really changed. Passengers are still flown on large jetliners by two or more highly trained human pilots functioning as a team.
The main reason why airlines are still decades away from pilotless planes boils down to the strict regulatory framework for aviation. At the heart of this regulation is certification—the process by which governmental authorities determine that an aircraft design is safe for flight. Even for conventional aircraft based on proven technologies, taking a concept from design through certification can require hundreds of millions of dollars and the better part of a decade. Tack on any novel technologies, such as the autonomy necessary to remove the pilot from the cockpit, and that process just gets longer and more expensive, with no guarantee of success.
Nevertheless, and despite the daunting odds against them, a new generation of startups is making a run at certifying autonomous passenger and cargo aircraft, in the process laying the groundwork for the next chapter of aviation. Instead of airliners, these companies are starting with small aircraft: electric air taxis and single-engine planes that typically seat fewer than a dozen people. Not only are the associated capital costs more manageable on a startup’s budget, there’s also a persuasive safety case to be made: Small aircraft are still prone to the types of accidents that have been largely eliminated from commercial airline operations. According to statistics compiled by the Aircraft Owners and Pilots Association, around 300 people die each year in small plane and helicopter crashes in the United States alone.
“Loss of control—mishandling the plane, usually as a result of disorientation or excessive workload—and controlled flight into terrain, [those] are the leading causes of accidents in small aircraft,” says Robert Rose, cofounder and CEO of Reliable Robotics, one of a few startups now working on retrofits that could enable Cessna Caravan planes to fly autonomously. A veteran of SpaceX and Tesla, Rose is adamant that “we, as a nation, possess the technology to prevent these accidents. If we can [autonomously] land a rocket on a small barge in the middle of the ocean, clearly we can find the centerline at an airport.”
The economic case for autonomy in aviation
While the safety argument for making small aircraft autonomous is a compelling one, the move is fundamentally rooted in economics. California-based Reliable Robotics and Massachusetts-based Merlin Labs are developing the commercial versions of their autonomous Caravans initially for the cargo feeder industry, which uses small airplanes to move packages to and from rural markets on behalf of carriers like FedEx and UPS. (Both companies also have military funding to develop autonomous aircraft.) Pilots for these feeder networks are typically flying alone, often at night and in bad weather, and their safety record is poor. This is a comparatively low-volume segment of the aviation industry, and there’s no money for second pilots and other risk mitigations typical of airline operations.
Reliable Robotics is one of a couple of companies that are outfitting Cessna Caravan airplanes with advanced software to provide a high level of autonomy, for applications that include cargo transportation. Reliable Robotics
The economic argument for autonomy is even more compelling in the emerging air-taxi industry, where hundreds of hopefuls—including a dozen or so serious contenders—are racing to develop electric vertical takeoff and landing aircraft to ferry passengers around crowded urban areas. Most of these eVTOLs are the size of helicopters, with space for just four or five passengers, and their proponents envision scores or even hundreds of them in the air over major cities, collectively moving millions of passengers annually. The concept is called urban air mobility, and in the speculative math that underpins it, eliminating the expense of a pilot and freeing up another seat for a paying passenger are seen as key to maximizing profits and scale.
China has already certified a pilotless air taxi: the EH216-S, a two-seat multicopter developed by Guangzhou-based EHang that in March obtained initial approval from the Civil Aviation Administration of China for limited commercial sightseeing operations. However, many Western observers doubt that EHang’s design would pass muster by the U.S. Federal Aviation Administration (FAA) or the European Union Aviation Safety Agency (EASA), both of which have an especially conservative approach to safety. For that reason, most Western eVTOL makers have opted to develop piloted aircraft first and plan to introduce autonomous versions at some later date. They figure that seeking certification of novel electric aircraft designs, even without autonomy, is already a big ask of these regulators.
A notable exception to this strategy is Wisk Aero, which began as a project funded by Google cofounder Larry Page and is now a wholly owned subsidiary of Boeing. In January 2022, the company declared that it would obtain FAA certification for its self-flying air taxi by the end of the decade and be operating close to 14 million flights annually within five years after that—a staggering ambition, given that the entire U.S. air traffic system currently manages around 16 million flights per year. While overheated expectations around urban air mobility have cooled considerably in the three years since that announcement, Wisk continues to forge ahead with its autonomous Generation 6 eVTOL, the company’s sixth aircraft design and the first it plans to certify for passenger-carrying operations.
A mockup of Wisk’s sixth generation of electric vertical takeoff and landing aircraft was unveiled in October 2022. Wisk
Importantly, Wisk, Reliable Robotics, and Merlin Labs aren’t just developing autonomous aircraft—they have already launched formal certification programs with the FAA. That means they’re working closely with the agency to define the rules and standards by which autonomous aircraft will be approved for commercial operations, blazing a trail for others to follow. The task is a daunting one, but the regulators and industry are not starting from scratch. Rather, they’re building on decades of certification experience and best practices that have helped to dramatically improve the safety of the aviation industry over its history.
Although the fatal January 2025 midair collision of an Army Black Hawk helicopter and an American Eagle CRJ700 near Washington, D.C.’s Reagan National Airport shook public confidence in the safety of the U.S. air transport system, commercial aviation remains a remarkably safe way to get around. According to researchers at MIT, the risk of a fatality from commercial air travel was just one per 13.7 million passenger boardings worldwide between 2018 and 2022. Fifty years earlier, the risk was an order of magnitude higher: one per 350,000 boardings between 1968 and 1977.
There are many reasons for this great leap in safety, and the certification process is an important one. Today, a majority of aviation accidents are attributed to human error, but that’s not because people are inherently less reliable than aircraft. It’s because a systematic approach to design and testing has over the past several decades eliminated many of the mechanical problems that used to cause accidents routinely. In this context, the argument for enhancing safety through autonomy can be thought of as transferring even more responsibilities from highly variable humans to engineered systems that can be subjected to greater scrutiny.
The overarching principle of certification is that the equipment and systems on an aircraft must be designed and installed so that they perform as intended during any foreseeable circumstances that they might encounter. “Perform as intended” includes not performing any unintended functions. An example of an unintended function is pushing the nose of an aircraft down past the level that a pilot can recover—that was the fatal result of a hidden software flaw that caused two crashes of the Boeing 737 Max and led to an extended grounding of the fleet while that oversight was remedied.
Another key principle of certification is that the probability of a failure condition must be inversely proportional to its consequences. In other words, the more serious the impact of a failure, the more remote its chances of occurrence need to be. Aircraft are complex machines with millions of components that can and do fail, but many of these components can fail with no serious effects. For example, it’s no big deal if a lightbulb in the cabin burns out on a regular basis. Certifying authorities like the FAA generally accept a high probability of failure conditions that have a negligible impact on safety. However, failure conditions that are potentially catastrophic are required to be “extremely improbable.”
Whether a failure condition is extremely improbable is fundamentally a qualitative evaluation that relies on the best judgments of engineers about how a system is likely to fail, supported by numerical assessments of the likelihood of failure. The critical systems on large commercial airliners are held to a numerical safety level of 10-9, meaning that catastrophic failures are expected no more than once in a billion flight hours (the equivalent of once in about 114,000 years of continuous operation).
Achieving such vanishingly low probabilities may require expensive, heavy, and redundant systems, so regulators typically relax the safety expectations for small aircraft that carry fewer people. For example, a four-seat airplane like a Cessna 172 may only be held to a numerical safety level of 10-6, meaning that catastrophic failures are expected no more than once in a million flight hours. That said, aircraft manufacturers are free to design to higher standards, and Wisk is targeting the highest numerical safety level, 10-9, for its Gen 6 eVTOL.
These basic principles of certification apply regardless of whether or not there’s a human pilot sitting in the cockpit, which is why developers of autonomous aircraft are confident they don’t need to completely reinvent the certification framework.
“Everybody thinks that you need to think about the autonomy a different way than you would think about a piloted aircraft,” says Cindy Comer, Wisk’s vice president of certification, safety management systems and quality. “But really we just don’t get to pass off these failure conditions to a pilot. We still do our safety assessment the same way. We still may design our aircraft in a very similar way, but it may be to higher levels, it may be with more redundancy, or maybe we add equipment, because we no longer have that person that can sit there and see the things, grab the things, to pull the breakers.
“So it drives our safety assessments to say, ‘Okay, we can’t put this on the pilot now. So what do we put it on?’”
Making autonomy certifiable presents unique challenges
Answering that question—What do we put it on?—for every foreseeable failure condition is where the real work of certifying an autonomous aircraft comes in. Conventionally piloted aircraft may use the same overarching framework for certification, but they have the advantage of decades of certification history and precedent to fill in all of the details, down to requirements for such things as the actuation of the landing gear and the markings of instruments and placards. For the new systems on autonomous aircraft, many of those details must be negotiated with the FAA or some other certifying authority, which must be convinced in each instance that the proposed solution is at least as safe as the approach used on conventional aircraft.
In the United States, applicants for type certificates have considerable flexibility in proposing how to meet the FAA’s safety goals. For each project incorporating novel technologies, the applicant and the agency agree on a set of requirements and standards, which becomes the “regulatory basis” for that aircraft. Theoretically, each autonomous-aircraft developer could have a very different regulatory basis, although in practice, the FAA looks for common ground. Nevertheless, the flexibility in this approach allows industry to explore a variety of possible ways to comply with a certification requirement before a solution is codified in regulation.
Merlin Labs launched the flight test campaign for its certification-ready autonomy system in June 2024. The Merlin Pilot system is integrated directly onto the aircraft and is intended in the near term to reduce crew workload rather than fully replace pilots.Merlin Labs
“Once you have the regulatory basis in place, then you need to come to agreement on how you’re going to demonstrate compliance to all of those regulations,” says Rose. “You can pull from existing standards, you can modify existing standards, or you can, in some cases, even just propose your own standards.” After agreeing upon the means of compliance, the applicant and regulator develop a detailed project plan that outlines the tests that will be performed and the reports—known as artifacts—that will be submitted to the regulator to support certification.
For conventional piloted aircraft with a history of real-world operations, much of how those aircraft will function in the national airspace system is assumed. “Large commercial airplanes operate from airports around the world with relatively known and static equipment that helps them navigate and approach and land,” says Brian Yutko, until recently Wisk’s CEO (he now heads commercial airplane product development at Boeing). This infrastructure, he adds, has been established over decades and is reflected in the design of aircraft in ways that are often taken for granted.
The existing system relies heavily on human pilots communicating with air traffic controllers over radio. Autonomous aircraft will require new concepts of operations, or “ConOps,” for how they will function, which could include using ground supervisors to handle radio calls, for example. In turn, the specifics of each ConOps will influence aircraft design requirements. According to Comer, crystallizing the ConOps at the beginning of the certification process “helps drive a common understanding of what you’re actually doing, and that may be different for every applicant with the FAA.”
Basically, Wisk intends for its autonomous air taxi, which Yutko has likened to “a tram in the sky,” to fly along very specific and limited routes with predetermined emergency landing locations. Such a narrow set of tasks is an easier thing to automate than the varied and flexible operations performed by most small piloted aircraft today (or, for that matter, most self-driving cars). Meanwhile, human supervisors on the ground will monitor flights and communicate with air traffic control as required.
Reliable Robotics’ automated Cessna Caravans will also have remote operators to handle communications with air traffic control, but they will fly over a much larger and more variable operating area. Because of this added complexity, Reliable has opted to split up the work of certifying its autonomous aircraft into chunks, beginning with certification of an advanced, always-on autopilot. This will assist but not replace the onboard pilot during all phases of flight, including landing as well as taxi and takeoff—which traditional autopilots are not capable of. Taking the pilot out of the cockpit will come as a follow-on certification project.
Autonomous aircraft will do what autopilots can’t
Proponents of autonomy like to point out that most commercial airline flights today are flown on autopilot from shortly after takeoff until touchdown or just before. It may therefore seem surprising that Europe’s aviation regulator, EASA, does not expect to see fully autonomous airliners until after 2050, while other regulators haven’t even speculated on a timeline for the shift.
There are several reasons why “solving” autonomy in aircraft is not just a matter of expanding the functionality of existing autopilots. Basic flight control—moving flight-control surfaces and power inputs to make an aircraft fly how and where you want—is a relatively simple thing to automate, and most of the time, when everything goes as expected, autopilot works just fine. However, most existing autopilot systems assume there’s a human pilot, and for that reason they aren’t reliable enough to enable full autonomy.
“There are autopilot actuators that go into aircraft today,” notes Reliable cofounder Rose. “But there’s a person sitting there monitoring them, and if [the actuators] do anything funny, then you click the off switch or actually, in many cases, you can just physically overpower the actuator. That’s not the case with ours—our actuators need to work all the time.”
More challenging is solving for situations when everything does not go as expected, such as when another aircraft conflicts with the programmed flight path or a stray vehicle blocks the assigned runway. Autonomous-aircraft developers can’t count on a remote operator to manage these types of urgent, sudden conflicts, because the command-and-control (C2) link between the ground and the aircraft could also fail.
“The aircraft, without having a [pilot] on board, needs to know where it is, and how to get where it’s going and how to avoid things along the way, over the length of its concept of operations,” says Yutko. Wisk’s Gen 6 flier will have the ability to safely complete a flight even if it loses both its C2 link and GPS signal immediately after takeoff, he says. “It turns out that if you don’t do that, then you start to impose really difficult technical requirements on the C2 link, or on your ability to maintain GPS.”
In the speculative math that underpins urban air mobility, eliminating the expense of a pilot and freeing up another seat for a paying passenger are seen as key to maximizing profits and scale.
Neither Wisk nor Reliable Robotics is using machine learning algorithms in its technical solutions, in large part because there’s no consensus on how to assure, to aviation’s exacting standards, the safety of such algorithms. These algorithms are frequently characterized as “nondeterministic,” meaning that their outputs can’t be reliably predicted from their inputs.
Some autonomous-aircraft developers are incorporating artificial intelligence into their designs. Merlin Labs, for example, is developing natural-language-processing algorithms to communicate with air traffic control. For the most part, however, autonomous-aircraft developers aren’t counting on technology alone to solve the innumerable contingencies that can arise in flight—that’s where the ground operators come in.
“We basically have taken everything that can be [automated] deterministically, and we’re making it deterministic,” Rose explains. “And all of the things that are…very hard to automate, that a human can do easily, then let the human do it.”
Which raises the question: If humans are required to supervise autonomous aircraft, does the business case for them still hold up? Their developers say it does, but in ways that aren’t as simple as just striking “pilots” from the balance sheet. For example, those remote supervisors will need training, but that’s likely to be far less extensive and costly than the training required to competently fly an aircraft. For Reliable Robotics and other companies targeting cargo delivery, autonomy also promises to improve the efficiency of the existing cargo feeder network.
“The reality is, in cargo aircraft, especially small cargo aircraft, pilots are super underutilized,” says Rose. Pilots at the feeder airlines may spend most of their day hanging out in a hotel room between their morning and evening flights. If people were instead managing autonomous cargo aircraft remotely, they could conceivably oversee additional flights across multiple time zones. “Our analysis has shown you can easily double the productivity of a pilot by putting them into our control center, potentially triple or quadruple the productivity [depending] on the mission set,” Rose says.
Autonomous tech might eventually trickle up
Even if companies like Wisk and Reliable Robotics succeed in certifying and commercializing their autonomous aircraft, human pilots still won’t face imminent extinction. Solving autonomy for one aircraft type and concept of operations doesn’t mean it’s solved for all types and concepts of operations. The technical, regulatory, and social barriers standing in the way of autonomous passenger jets are formidable.
“I think for as long as we’re all alive, there will be piloted large commercial aircraft,” Yutko says. “If you solve Gen 6, you don’t get uncrewed large airplanes. You just don’t, and I’m not certain that we will in our lifetimes.” However, he does think it likely that some of the technologies now being developed at Wisk—such as navigating in the absence of GPS or techniques for automating emergency checklists—will find their way into conventionally piloted aircraft in ways that enhance safety.
“I think those will be the types of things that we see in our lifetime benefiting big commercial transport applications, and I think it’s phenomenal,” adds Comer.
As for whether it makes sense for anyone to embark upon a career as an airline pilot under the looming shadow of autonomy, it probably still does, at least for now. But check back in another 20 years.
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