Photography by Anant Sinha

In the history of aviation, few crafts have captured the imagination quite like the ekranoplan: part aircraft, part ship, and entirely unconventional. Riding on a cushion of air just above the water’s surface, these vehicles harness the aerodynamic phenomenon known as ground effect. 

The Soviets designed aircraft to skim the ocean, evading radar detection and maximizing fuel efficiency. But when the Soviet Union collapsed, its ekranoplan program withered, and died before 2000. In the middle of San Francisco, three young founders are trying to bring that dream back to life.

Inside a sprawling 15,000-square-foot warehouse, Poseidon Aerospace is building ground effect aircraft designed to move faster, cheaper, and with military-grade stealth. The high ceilings echo with the hum of machinery. Workbenches are stacked with carbon fiber sheets and precision-cut aluminum. A few blocks away, the waterfront provides the perfect testing ground.

Isaac Baumstark and David Zagaynov, now co-CEOs, met at a dinner party in 2023. They were both interested in aerospace. Soon after, they brought on Parker Tenney—David’s then roommate and a former Lockheed Martin engineer—as CTO, rounding out the founding team. Inspired by the airship product Sergey Brin had been toying with, a 400-foot prototype built to revolutionize freight and passenger transport with carbon-neutral technology, they saw an opportunity to breathe new life into a long-forgotten technology.

Despite its size, the Poseidon warehouse is not exactly a high-budget aerospace facility — yet. Office furniture is salvaged from Facebook Marketplace (the entire setup costs less than $200, apparently). Even their CNC machine—a piece of equipment that normally runs in the tens of thousands of dollars—was thrifted. Nearly all its materials are sourced from the United States. The carbon fiber and batteries come from Livermore, California — in the foothills across the San Francisco Bay. Poseidon builds every mold plug, tooling piece, carbon fiber rib, and wiring harness in-house, ensuring complete control over quality and production. Thousands of hours of sanding, refining, and perfecting go into each component. 

​​At first, it was just the three of them. The company ran on maxed-out credit cards, secondhand 3D printers, and a willingness by the founders to get their hands dirty—literally. Their first prototype, Poseidon V0, was built with just a few thousand dollars worth of material. A Class A ground-effect vehicle with a box-wing design, it skimmed just above the water’s surface. It was elegant, but limited. Harsh weather exposed its flaws. 

Their first investor demo was at 1 AM, at a park with a duck pond—the “nastiest lake you can imagine.” David had to strip naked, jump in, and wade through the slime just to get the prototype ready. The scrappiness and determination convinced investors. They have raised $1.4 million so far, including from Starship Ventures and Draper Startup House.

One early test almost cost Isaac his life. Flying a six-foot prototype in Burlingame, it lost telemetry in rough waters just 30 minutes before sundown. With the sun disappearing fast, Isaac paddled out to retrieve it, but his board started sinking. One hundred yards from shore, with the darkness closing in, concerned citizens called the police. By the time Isaac made it back to safety, he was practically frozen and spent the night thawing in the shower. They now have a boat for future tests.

The idea of the ekranoplan dates as early as the 1920s, with formal studies emerging in the 1930s. But it was in the 1960s that two pioneering engineers—Rostislav Alexeyev in the Soviet Union and Alexander Lippisch in Germany and the United States—independently turned the concept into reality. Alexeyev, a visionary ship designer, led the Soviet ekranoplan program, creating massive military vehicles. A 550-ton Caspian Sea Monster, his most legendary creation, bewildered U.S. intelligence analysts in the 1960s when satellite images showed a massive craft with wings that seemed to operate on water, defying categories and raising espionage concerns.

Other nations also explored ground-effect vehicles, though none at the same scale. The United States conducted GEV research during the 1950s and 1960s, culminating in projects like Boeing’s Pelican and, more recently, DARPA’s 2022 Liberty Lifter. Meanwhile, Germany, under Lippisch and later Hanno Fischer, pursued commercial passenger ekranoplans, resulting in the AirFish 8. Even Iran deployed small military models, such as the Bavar 2, for surveillance missions in 2010.

A Machine of Speed and Stealth

Unlike traditional aircraft or boats, the Seagull is a ground-effect vehicle that balances the speed of flight with the efficiency of maritime travel. This 13-foot craft boasts a 120-mile range and can carry a 45-pound payload. In contrast to Poseidon V0, it is a Class C ground effect vehicle: optimized for efficient low-altitude flight, but capable of briefly lifting above surface turbulence and obstacles when needed.

Designed for high-speed, fuel-efficient transport over water, Seagull relies on a combination of avionics, autonomy, and real-time telemetry to fly smoothly. It’s equipped with Starlink internet and a flight computer that constantly processes sensor data to adjust altitude, speed, and stability. While it skims just above the surface, its ground control system monitors long-range telemetry, ensuring smooth and efficient operation. The vehicle is fully autonomous, reducing the need for human intervention and optimizing performance for both safety and efficiency.

Seagull operates in a unique “Goldilocks zone”—too high for sonar, too low for radar. It can loiter. It can surveil. It can move heavier payloads than drones and reach areas inaccessible to traditional vehicles, particularly regions without airport infrastructure or safe landing zones.

A silent, fast-moving platform that can deploy payloads where needed, Seagull offers a new frontier in anti-submarine warfare. It can monitor undetected, gathering intelligence or delivering equipment where submarines or other naval assets cannot reach. In coastal surveillance, it provides an unseen eye over contested waters, moving faster than traditional reconnaissance vessels, and without the need for extensive infrastructure.

Over the past century and a half, there have been advancements in ship design, fuel efficiency, and containerization — not to mention advancements in aviation. Not so with the fundamentals of cargo transport. We have relied on large, slow-moving vessels to move heavy cargo since the introduction of steamships in the 19th century. Those ships are better today, to be sure. But cargo ships still travel at an average speed of 15-25 knots. Innovations like airships or faster ocean liners were either limited to passenger transport or discontinued because they were impractical.

Given that most of the world’s population lives near water, the opportunity for large ground effect vehicles is a big one. They can take off and land on water, eliminating the need for runways or ports. And they can move much faster across water than ships. In Puerto Rico, a major hub for medical manufacturing, the current reliance on slow, expensive cold storage shipments creates inefficiencies that a ground effect vehicle’s speed and accessibility can eliminate. 

Poseidon has already caught interest in Greece. With over 200 islands, many of which lack airstrips, traditional cargo transport is either slow by boat or expensive by helicopter. Being able to rapidly deliver goods without requiring additional infrastructure has already attracted the attention of drone delivery companies in the region, offering a faster, more cost-effective solution for island logistics.

Seagull is the beginning of the Poseidon adventure. In two years, the team hopes to have a 50-foot version of Seagull operational—capable of carrying two tons across 1,500 miles. If they succeed in making an economically-viable product, it’d unlock the next phase: a full-scale factory for mass production. From there, the vision only expands, and 50-feet starts to look small. In the meantime, the team is trying to move fast — so that we can, too.