Alteon plans aircraft that can stay airborne for months without fuel

Bengaluru startup Alteon is developing autonomous aircraft that use dynamic soaring, inspired by albatross flight, to remain airborne for months and monitor oceans continuously

Samay Sanghvi, 20, is trying to tackle a problem that has hampered aviation since its earliest days: aircraft need to land. His Bengaluru startup, Alteon, is developing an aircraft designed to stay airborne for months by harvesting energy from wind gradients above the ocean instead of fuel.

 

The design mimics the albatross, which can travel 800 to 1,000 kilometres a day without flapping its wings, using a technique called dynamic soaring. In an August test, Alteon's aircraft autonomously flew repeated loops less than a metre above the open ocean.

 

The milestone helped Alteon secure $2.5 million in pre-seed funding, on a bet that such aircraft could monitor oceans continuously. This can be done at a fraction of the cost of ships or satellites.

 

Aviation has continually pushed the limits of aircraft performance, but one constraint has remained: aircraft still have to land for refuelling, maintenance, and recovery. Alteon has spent more than a year developing an aircraft engineered to remain airborne for months.

 

The firm is developing autonomous dynamic-soaring vehicles that extract energy from wind gradients, as albatrosses do, to remain airborne for extended periods. A key engineering challenge is performing this close to the surface of a moving ocean.

 

An early August offshore flight test cleared a major technical hurdle on the path to sustained dynamic soaring. It demonstrated that the aircraft could fly the aggressive manoeuvre in real offshore conditions.

 

"Today we already know that it is possible to gain energy from the wind using dynamic soaring," said Sanghvi. "Building aircraft that fly for over a year using it, is not a matter of a single technical breakthrough but a matter of solving a range of challenging engineering problems across autonomy, structures, aero and more."

 

Sanghvi's path to Alteon began years earlier. Sanghvi, who grew up in Mumbai, began experimenting with ventures early. At 14, during the Covid lockdowns, he traded futures and later launched two startups, in edtech and freelance marketplaces. Both failed.

 

A couple of years later, he went through what he calls an existential reset, which drove him to look for ways to have a larger impact on society.

 

He then spent months learning and building, aided by a small grant to tinker with hardware. His experiments ranged from forging a Japanese katana to flying radio-controlled aircraft, each one revealing what he didn't yet understand. Over time, his focus narrowed to aircraft.

 

He learned by building, flying, and crashing successive models, then developing his own prototypes. By 2023, straight out of high school, he was working full time on what would become Alteon. Early funding came from Emergent Ventures and the Atlas Fellowship: Rs 4 lakh, enough to start. 1517 backed him after that. He incorporated Alteon in 2025. Today Alteon is a growing team of 20, based in Bengaluru.

 

Alteon's next phase of testing will focus on harvesting wind energy until the aircraft can sustain flight without propulsion, much like an albatross.

 

Alteon recently raised $2.5 million in pre-seed funding led by Lachy Groom, known as a co-founder of AI robotics company Physical Intelligence and an early Stripe employee. There was participation from the Together Fund as well.

 

"Samay and team are making remarkable progress toward building an airplane that can stay aloft for more than a year at a time," said Lachy Groom, investor and co-founder of Physical Intelligence. "If they get this right, we could soon have millions of them - essentially parked in the sky - doing things that today require large ships, crews and huge amounts of infrastructure."

 

The funding will take Alteon from August's offshore milestone toward autonomous dynamic soaring without propulsion. It would also help scale up R&D toward deploying a fleet over the ocean.

 

The objective is not simply longer flights but continuous, autonomous presence over the ocean. Together, these fleets would offer real-time ocean coverage at a fraction of the cost of ships, satellites or offshore installations.

 

These fleets can carry payloads for applications from mapping ocean conditions to monitoring infrastructure, to coordinating defence and search-and-rescue systems.

 

A fleet that stays airborne for months can observe activity continuously rather than through periodic patrol. This helps authorities detect and deter illegal fishing, drug trafficking, and security threats such as those exposed by the 26/11 Mumbai attacks.

 

Ships broadcast their position via the automatic identification system (AIS), a self-reported system that is easy to falsify. On land, a GPS claim can be checked against traffic cameras; offshore, no equivalent, persistent verification exists.

 

Satellites and conventional aircraft are constrained by revisit cycles and operating windows, leaving long gaps between observations over open ocean. Alteon's aircraft are designed to close that gap. A fleet can be tasked to revisit an area every few minutes to once an hour, depending on the mission, rather than the limits of the platform.

 

“The ocean is the biggest unwatched surface on the planet, and the bottleneck has always been endurance: every aircraft ever built has had to land,” said Shubham Gupta, co-founder, Together Fund. “Alteon removes that assumption entirely, with an aircraft that flies itself, charges itself from the wind, and stays up for months.”