In this episode of our ‘Sustainability in the Air’ podcast, Billy Thalheimer, co-founder and CEO of REGENT, speaks with SimpliFlying CEO Shashank Nigam about how his company is developing Seagliders, which are all-electric flying boats that create an entirely new category of transportation between boats and aircraft.

REGENT’s groundbreaking technology has secured over $10 billion in orders from airlines, ferry operators, and energy companies globally. The company’s first vehicle, the Viceroy, can carry 12 passengers and two crew members across 180 miles at 180 miles per hour, operating just 30 feet above the water’s surface. A larger 100-passenger Monarch variant is also in development.

Here are the key highlights of the conversation:

• Solving the regional travel gap (4:50)
• Three breakthrough technologies: hydrofoils, ground effect, digital flight controls (11:36)
• Maritime certification pathway (20:29)
• Commercial and defence applications at scale (26:55)
• Infrastructure advantages and electrification (33:57)
• The listen-first approach: lessons from Hawaii (30:20)
• Rapid fire! (43:35)
  
  
  

Keep reading for a detailed overview of the episode.

Why Seagliders represent a breakthrough in wing-in-ground technology

To understand REGENT's Seagliders, it helps to start with the technology they build on. Wing-in-ground (WIG) craft have been around for decades — vehicles designed to fly just above the surface, using the aerodynamic “ground effect” to generate efficient lift. The Soviet Union’s Caspian Sea Monster, a gigantic low-flying prototype from the 1960s, remains the most famous example.

But despite the promise, commercialization efforts repeatedly stalled. As Billy Thalheimer notes, the early designs were held back by three persistent issues: “poor wave tolerance, poor maneuverability, and poor safety.”

REGENT’s innovation lies in combining multiple technologies to overcome each of these problems. The company integrates hydrofoil systems borrowed from advanced yacht racing, WIG aerodynamics, and sophisticated digital flight controls into a single vehicle that operates in three distinct modes: float, foil, and fly.

One such weakness of past designs was the reliance on planning hulls — flat-bottom structures similar to those on speedboats. They performed adequately in calm water but became unstable as conditions worsened. “At best, it’s uncomfortable. At worst, you can’t take off at all,” Thalheimer says.

The hydrofoil system addresses both wave tolerance and maneuverability. “Hydrofoils are underwater wings,” he explains. “They lift the Seaglider out of the water, giving us five feet of wave tolerance. So now we can operate in over 90% of conditions globally and be very reliable.” Once on foils — at up to 50 miles per hour — the vehicle remains classified as a boat but benefits from the agility seen in America’s Cup and SailGP yacht racing.

Safety, the other major shortcoming of earlier WIG craft, is addressed through digital flight controls. REGENT automates the transitions between floating, foiling, and flying so operators aren’t managing complex aerodynamic and hydrodynamic states in real time. “We have 12 sensors controlling the Seaglider in space and altitude. We have triple redundant computer systems, quadruple redundant power buses,” Thalheimer explains.

The result is a simplified user experience: “You drive a Seaglider like you drive a boat. The only controls available to the operator, who is a mariner and not a pilot, are boat controls, left and right, fast and slow, and the system takes care of the rest.”

REGENT’s flagship Seaglider vessel, Viceroy.

4 takeaways from the conversation

1. Filling a critical gap in regional transportation

REGENT seeks to address a transportation problem that has gone largely unchanged for more than 70 years. Using the Boston–New York corridor as an example, Thalheimer notes that journey times have barely shifted since the mid-20th century.

“If you look back to the 1950s, that route would take several hours driving in an old car. And if you look at it today, it’s the exact same time! Everything about the world has changed: medicine, the internet, and AI. But that route still takes the same.”

This pattern extends far beyond the U.S., especially for the 40% of the global population living in coastal regions, says Thalheimer. The challenge is especially acute on 50–200 mile journeys, where driving, ferries, rail, and regional flights often deliver similar door-to-door times.

Seagliders are designed to be “simultaneously the fastest, cheapest, greenest, safest, and most comfortable way to travel on these routes.” The technology essentially creates high-speed rail without the billions required for rail infrastructure, says Thalheimer.

“Why build roads and rails and airports when you have this open water, and we can leverage that open water for this very efficient transportation, flying on that cushion of air like the birds do.”

The Viceroy’s 180-mile range in its all-electric configuration covers these short-regional missions. A hybrid variant, currently in development for defence applications, extends range to 1,600 miles by replacing half the battery system with a turbogenerator.

2. Maritime certification provides a faster pathway to market

One of REGENT’s most significant advantages is regulatory: Seagliders are certificated as maritime vessels, not aircraft. This applies both internationally and in the United States, where wing-in-ground craft are defined in Title 46 of the U.S. Code.

The rationale is straightforward: WIG craft operate below the height of sailboat masts and cruise ships, placing them firmly within the maritime domain, explains Thalheimer.

International rules established in 2018 by the International Maritime Organization (IMO) and the International Civil Aviation Organization (ICAO) outline three categories of WIG craft. “Type A, which is what a Seaglider is. It stays in ground effect at all times; dock-to-dock over water only,” says Thalheimer.

More complex Type B and Type C variants, which operate beyond ground effect, fall under different regulatory frameworks and regulatory bodies. REGENT has intentionally focused on the Type A category, which keeps the Seaglider certification under the Coast Guard jurisdiction nationally and IMO internationally.

This maritime certification pathway also addresses the regional pilot shortage. “We get access to a much wider pool of master mariners and professional seafarers; people who would normally operate a passenger ferry or similar vessel, and who can take a REGENT Seaglider course. It’s around six weeks of training to earn their certification as a Seaglider captain.”

3. Diverse applications driving $10 billion order book

Demand for seagliders is coming from three distinct markets: commercial aviation, maritime operators, and defence and energy clients.

“Our order book now stands at $10 billion, and it is broadly split between maritime operators looking for faster, greener travel using their existing docks, crews and routes, and aviation customers seeking a cheaper and greener option,” Thalheimer explains.

Commercial aviation customers include Mesa and Hawaiian Airlines, attracted by the economics and the ability to serve challenging regional routes more efficiently.

On the maritime side, ferry operators like UrbanLink are planning large-scale deployments. UrbanLink alone aims to serve four million passengers annually on routes like Miami to West Palm Beach, a journey that currently takes two hours by car but would take just 35 minutes via Seagliders.

REGENT also has partnerships with Ørsted, TotalEnergies, and ADNOC, which focus on serving offshore wind farms and oil platforms. “Helicopters are very expensive to get out there, require tonnes of training, huge maintenance costs, plus the safety implications of flying helicopters over the water,” Thalheimer says. Seagliders, he argues, can carry out these missions “for a fraction of the cost, a fraction of the time, with higher safety.”

REGENT has also extended its contract with the U.S. Marine Corps Warfighting Lab (MCWL), in an agreement currently estimated at $10 million. The renewed agreement follows the successful completion of REGENT’s $4.75 million contract with MCWL.

4. Community engagement and infrastructure strategy

A defining feature of REGENT’s approach is what Thalheimer describes as “listen first.” This philosophy stems from the missteps of Hawaii’s SuperFerry, which collapsed after attempting to bypass environmental review processes and ignoring community concerns.

In contrast, REGENT began its work in Hawaii with what it calls a “listening tour”, holding over 200 meetings across the state with local community groups, tourism bodies, and government and state entities. This resulted in the Hawai’i Seaglider Initiative, a coalition advancing awareness and adoption of sea gliders in Hawai’i​, with a focus on community, culture, and environment.

“It is not one size fits all. It’s very market specific,” Thalheimer emphasises. REGENT has now replicated this model globally with Japan Seaglider Initiative, Miami Seaglider Initiative, and Rhode Island Seaglider Initiative, each tailored to local needs and concerns.

From an infrastructure standpoint, the company’s needs are intentionally light. “We can use existing docks, and I think in the early days of Seaglider operations, in most cases, we will,” Thalheimer says. The vehicles primarily require access to charging infrastructure, which can be integrated with existing port electrification projects or local micro-grids.

REGENT’s development timeline is advancing rapidly. By early 2026, the company expects to achieve the world’s first wing-in-ground effect classification, a milestone that will validate the technology for commercial deployment.