Driven by the escalating global appetite for air travel, aviation emissions have outpaced those from other modes of transport such as rail, road, or shipping in recent years. The quest for reversing this trend is a slow and steady process. Sustainable Aviation Fuel (SAF), which has the potential to reduce emissions by up to 80% when produced and utilized efficiently, could account for two-thirds of the emission reduction needed to achieve the aviation industry's net-zero target by 2050. However, SAF is currently scarce, and even in the most optimistic scenarios, it is projected to represent only 0.53% of total jet fuel consumption in 2024, far from the levels necessary to make a significant environmental impact. Amidst the scramble by airlines and regulators to find ways to decarbonize the industry, some engineers are advocating for a radical shift in aircraft design to significantly reduce fuel consumption and, consequently, emissions. This involves abandoning the traditional "tube and wing" configuration that has dominated commercial aviation for a century in favor of a "blended wing body" design, where the wing area occupies a substantial portion of the fuselage, resulting in a distinctive aircraft silhouette.

In 2020, Airbus ventured into this territory by creating a small-scale, remotely-piloted blended wing prototype to test a design that the company claimed could save up to 20% on fuel. Following suit in 2023, California-based JetZero announced its plans for an aircraft with a similar design, capable of accommodating over 200 passengers, with an ambitious aim to begin operations by 2030. Now, San Diego-based Natilus has entered the fray with Horizon, a blended wing aircraft designed to carry approximately 200 passengers while emitting half the emissions and consuming 30% less fuel than current Boeing 737 and Airbus A320 models— the very aircraft it intends to rival. "The narrow-body market, which is precisely where Horizon is positioned, will be the largest market over the next two decades," asserts Aleksey Matyushev, CEO and co-founder of Natilus. "Given all the challenges the industry is facing, I believe there's an unprecedented opportunity to build an equivalent to a Boeing or Airbus for the first time ever." Founded in 2016, Natilus had previously unveiled a cargo-only, unmanned plane named Kona that also employs the same innovative shape. Matyushev traces the origins of the blended wing body design back to the 1990s with McDonnell Douglas, a significant American aerospace manufacturer that later merged with Boeing in 1997. Although Boeing never commercialized a blended wing aircraft, they did explore the concept and developed an unmanned prototype, the X-48. Natilus reports that Kona has garnered 400 orders, with a full-scale model set to be constructed and flown within the next two years. Much of the technology from Kona is expected to be transferred to Horizon, which will feature a conventional cockpit and crew, with Matyushev stating that it aims to enter service by 2030—a highly ambitious goal, as it would be an unprecedented feat for a completely new aircraft to move from design to full certification in just six years.

"One of the challenges with the blended wing body design is stability and control," Matyushev explains. "I believe that's where McDonnell Douglas and Boeing really struggled—how do you stabilize the aircraft?" He suggests that one method to achieve stabilization is through sophisticated flight control systems—essentially computers, which Matyushev notes have been problematic with the Boeing 737 Max. The alternative is aerodynamics, or the design of the aircraft's surfaces, which is the path Natilus has chosen and also what distinguishes it from JetZero, according to Matyushev. The new shape offers several crucial advantages. "There's a 30% reduction in drag, but concurrently, you can actually decrease the aircraft's weight to accommodate the same number of passengers or cargo, which is quite unique," he says. "With a smaller aircraft, you have smaller engines, leading to less fuel consumption. So when you combine these factors, it results in a reduction of emissions per passenger seat by approximately 50%." The significantly larger fuselage, which no longer resembles a tube, opens up possibilities for different cabin layouts. "We have about 30% more floor space than a conventional aircraft," Matyushev explains. "So many of our customers are contemplating an enhanced passenger experience. Could we reintroduce the lounge? Are there other spaces within the aircraft that could be designated for those long-haul flights?" Not every aspect of Horizon will be groundbreaking; for instance, the aircraft will utilize existing engine technology, ruling out hydrogen or electric options. "There's a common saying in aviation—never put a brand-new engine on a brand-new aircraft. That's too risky," Matyushev says. For the same reason, Horizon is designed to fit into the same spaces as a Boeing 737 or Airbus A320, necessitating no changes to airport infrastructure.

According to Gary Crichlow, an aviation analyst at Aviation News Limited, a series of delivery setbacks that have left airlines waiting for new aircraft well into the 2030s has opened a "window of opportunity" for a newcomer to disrupt the established order. "That window, however, is very narrow," he says. "A key selling point for operators is the commonality in terms of flight crew qualifications. The success of the 737 Max and A320neo can be largely attributed to their ability to be easily integrated into existing 737 and A320 operations, respectively: flight crews require minimal additional training to transition." However, initial issues are a common occurrence with every new aircraft, and with a new, untested manufacturer and an unproven design, these are almost certain. "(Horizon) will feature a completely different seating and cargo loading plan, necessitating entirely different flight and cabin crew. Avoiding that operational headache and providing reliable support at scale when it arises is likely the most significant challenge that Natilus will face in persuading potential customers to opt for the Horizon over waiting for a more traditional 737 Max or A320neo replacement," Crichlow adds. He also highlights potential obstacles on the plane's path to certification with aviation authorities. "The challenge for any clean-sheet design has always been the substantial upfront cost to develop and certify it. In terms of certification, conventional aircraft such as the 737 Max 7 and 10, the 777-X, the A321neo XLR, and COMAC C919 have all faced, and in some cases are still facing, significant regulatory delays compared to their manufacturers' original timelines. With a design as distinct as the blended wing body, I would anticipate regulators to be even more cautious." Matyushev is cognizant that Natilus is venturing into uncharted territory: "There are numerous questions about how to construct a blended body at full scale, as all we have at present is wind tunnel data and scale prototypes, but no one has actually built one at full scale," he says. With Natilus currently working on a full-scale prototype, some of those questions may soon be resolved.