AIRSHIP is an ambitious project developing autonomous, electric ground-effect craft for efficient and sustainable water-based cargo transport.
The idea of using the aerodynamic ground effect for transportation has been explored since the early years of aviation. When flying close to a surface, typically less than half a wingspan above it, the interaction between the wing and the ground improves its lift-to-drag ratio and increases efficiency. This effect allows a vehicle to carry more payload or reduce energy consumption compared with conventional aircraft flying at higher altitudes.
Early prototypes appeared in Finland in the 1930s with the work of engineer Toivo Kaario, often credited as the pioneer of the ground-effect vehicles, known also as wing-in-ground (WIG) vehicles or ekranoplans. In the post-war years, German engineer Alexander Lippisch developed the reverse-delta wing, a configuration that improved stability for WIG vehicles. The Soviet Union pushed the concept furthest, building a series of ekranoplans, including the 92m-long Caspian Sea Monster, with maximum take-off weight of 544t with maximum speed of 500km/h.
Other attempts have appeared since then, including concepts from Boeing (Pelican ULTRA), projects in Europe and Asia, and most recently designs such as the Airfish-8 in Singapore and the REGENT Seaglider in the US. Despite these efforts, WIG vehicles have remained rare. Their potential advantages in efficiency and payload are clear, but technical challenges in control, stability, and regulation have prevented wider adoption.
Today, advances in autonomous control systems, electric propulsion, and digital simulation make it possible to revisit the idea. The Horizon Europe project AIRSHIP is developing a new class of ground-effect craft, referred to as unmanned WIG vehicles (UWVs), with the goal of producing an autonomous, all-electric vehicle for cargo transport in coastal and inland waters.
What is ground effect?
When flying close to the surface – water, ice, or land – the interaction with the ground changes the way air flows around the wing. The swirling vortices that normally form at the wingtips weaken, drag drops, and lift becomes more efficient.
Nature uses this trick too. Large seabirds like pelicans and albatrosses instinctively exploit ground effect when skimming just above the waves. By flying low, they save energy on long migrations. Pilots also know the effect intuitively. During landing, as the aircraft flares close to the runway, it seems to ‘float’ – that’s ground effect in action.
WIG vehicles are designed to exploit this phenomenon deliberately and continuously, cruising just a few metres above the surface for maximum efficiency. The effect is strongest when the wing flies at a height less than about one wingspan above the surface. The closer it gets, the greater the benefit. The gain can be substantial: lower fuel consumption, higher payload capacity, or longer range.
However, the benefits come with challenges. In ground effect, the coupling between lift, drag, and altitude is highly nonlinear. Small variations in height can change forces significantly, and waves add additional disturbances. This makes the vehicle difficult to control without advanced systems.
The AIRSHIP project
AIRSHIP is a Horizon Europe research and innovation project funded under the Climate, Energy and Mobility cluster, managed by CINEA – the European Climate, Infrastructure and Environment Executive Agency. The project began in January 2023 and will run for four years, with a total budget of €5.1m. It is supported under the call HORIZON-CL5-2022-D5-01: Clean and competitive solutions for all transport modes.
The consortium is co-ordinated by the Universidad Politécnica de Madrid (UPM) through its Center of Automation and Robotics (CAR-CSIC). UPM also participates with its Center of Industrial Electronics (CEI). The partners include Tampere University in Finland, Tallinn University of Technology (TalTech) in Estonia, the University of Luxembourg, and INESC TEC Research Institute in Portugal, along with two SMEs: the La Palma Research Centre in Spain and Trisolaris Advanced Technologies in Portugal.
AIRSHIP’s objective is to lay the foundations of a new class of fully electric, unmanned wing-in-ground vehicles (UWV). By combining aerodynamic efficiency, zero-emission propulsion, and advanced autonomy, the project aims to demonstrate a sustainable alternative for transporting goods across archipelagos, inland seas, and large lakes.
The project envisions cargo craft that inherit the speed and flexibility of aircraft while operating with the energy efficiency and reduced environmental footprint closer to ships. This balance is expected to enable new business models that are both climate-friendly and commercially competitive. We want to serve as a stepping-stone towards future all-electric craft, and produce a technology roadmap for broader applications, including emergency response, search and rescue, and operations in open-sea environments.
Operational and technical requirements and economic feasibility
The AIRSHIP design, led by Tampere University, is defined by operational and technical requirements that ensure its performance and competitiveness. The operational requirements address market-driven needs such as range, payload, and regulatory compliance, ensuring viability against existing transport modes. The technical requirements translate these goals into engineering criteria, covering aerodynamics, propulsion, and structural efficiency.
The goal is a craft with higher range, payload capacity, and energy efficiency than current alternatives, while remaining reliable in demanding environments. The same platform is intended to support multiple use cases, from cargo logistics to medical delivery, disaster response, and offshore operations.
Wave tolerance
The craft is designed to tolerate wave heights of up to 3.3m during cruise. This figure is based on Europe’s long-term maximum significant wave height of 2.20m, observed in the Canary Islands during winter. An efficient cruise value of 1.30m reflects calmer conditions typical of the Mediterranean and Baltic Seas. This tolerance ensures year-round operability in different European waters.
Range
The target range is 1,000km with full payload, enabling direct connections between archipelagos and the mainland without intermediate stops.
Cargo space dimensions
The cargo bay is designed with dimensions of 8.0m × 2.2m × 1.9m, comparable to the cabins of business jets. This allows transport of high-value goods, time-sensitive supplies, or, in some cases, passenger-equivalent loads. The vehicle is planned to carry up to 7t of cargo.
Lift-to-drag ratio
A target value of 18.5 has been set, reflecting efficiency gains compared with regional aircraft such as the ATR 72.
Use-case scenarios
While the primary focus is cargo logistics, the design also considers applications such as the delivery of medical supplies, disaster relief in coastal regions, and support for offshore or Arctic operations.
Regulatory framework
AIRSHIP is not classified as an aircraft but as a ship, under the International Maritime Organization (IMO). This distinction changes everything from certification to operations. The IMO and the International Civil Aviation Organization (ICAO) agreed in the 1990s to divide ground-effect craft into three categories. Type A craft fly only in ground effect and fall entirely under IMO rules; Type B may briefly climb up to about 150m, and Type C can operate higher and fall partly under ICAO rules.
AIRSHIP is designed as a Type A WIG, meaning it will remain within ground effect and be treated as a ship. The IMO issued updated guidelines for WIG craft in 2018 (MSC.1/Circular 1592), covering issues such as safety, operational range, and navigation. These guidelines, however, were written with piloted craft in mind. AIRSHIP, being unmanned and AI-driven, sits in a regulatory grey zone. For that reason, the project also considers emerging IMO frameworks for Maritime Autonomous Surface Ships (MASS), along with new EU-level AI regulations.
Another important limitation is that the IMO guidelines only apply to WIGs above certain thresholds (carrying more than 12 passengers or above 10t of displacement, and operating internationally within 200 nautical miles of port). While AIRSHIP’s cargo model falls within these definitions, its autonomous nature means future certification will likely blend existing WIG rules with MASS provisions.
This dual status — ship by classification, autonomous system by function — is one of the challenges that makes AIRSHIP not just a technical demonstration, but also a regulatory pathfinder.
Economic feasibility
Alongside the technical and operational requirements, AIRSHIP also considers the economic dimension of deploying WIG craft. Researchers at TalTech have developed an open-access route-level simulator to evaluate feasibility, using scenarios such as inter-island transport in the Canary Islands. The tool integrates revenues, operating costs, capital expenses, and financing conditions, incorporating uncertainty via Monte Carlo simulations. The simulator, available here, allows stakeholders to explore different business cases and access AIRSHIP performance under various operational and financial conditions.
AIRSHIP prototypes
To translate design requirements into reality, we are developing a series of prototypes at different scales.
A0-W: A 1:50 model for water channel and wind tunnel tests, used to study aerodynamic and hydrodynamic behaviour.
A0-S: A 1:10 flying model to test aerodynamics and control strategies; already flown in environments ranging from frozen lakes to indoor pools.
A1: A 1:5 demonstrator with a 5m wingspan and semi-autonomous control, integrating propulsion, guidance, and perception systems in real-world sea trials.
Commercial concept (CC): Full-scale 25m design capable of carrying 7t of cargo over 1,000km at 220km/h; not built in the project, but used for market and scaling studies.
We are currently building a 5m wingspan, demonstrator, which we’ll demonstrate in real sea environments in autumn 2026.
Enabling technologies
The AIRSHIP project introduces several technological innovations that collectively define a new class of autonomous, zero-emission WIG craft. These novelties go beyond incremental improvements, aiming to overcome the limitations that historically prevented WIG vehicles from becoming practical and commercially viable.
Zero-emission propulsion and power
UPM-CEI leads the development of AIRSHIP’s zero-emission propulsion and power systems, integrating integrating multiple energy technologies into a scalable system. Prototypes rely on lithium-ion batteries for lightweight and efficient power, while larger demonstrators will combine hydrogen fuel cells for steady cruise with batteries; and supercapacitors for peak loads, such as during take-off when hydrodynamic resistance is highest. Supplementary solar panels and shore-based renewable infrastructure – including hydrogen production through electrolysis – are considered to support long-term sustainability. This integrated approach provides both operational flexibility and a pathway to fully zero-emission transport.
Energy storage
Lithium-ion batteries power prototypes and near-term vehicles.
Supercapacitors to handle short bursts of power, particularly during take-off.
Fuel cells are planned for larger demonstrators, providing steady cruise power with batteries covering peak demand.
Solar panels as supplementary sources to reduce idle emissions and provide trickle charging.
Autonomous control
Controlling a WIG vehicle is fundamentally challenging. Flying just a few metres above the waves means that small altitude changes can strongly affect lift, drag, and stability. Gusts, turbulence, and the transition between waterborne and airborne motion make manual operation difficult, which is why advanced autonomy is essential.
Because of the highly dynamic nature of ground effect, the system must adapt continuously to changing conditions. Maintaining the right altitude relative to wave height is critical for efficiency, and smooth transitions between waterborne and airborne states are essential for safety. To achieve this, AIRSHIP combines proven control methods with advanced approaches such as predictive algorithms and learning-based techniques.
UPM-CAR researchers are working on traditional control methods, such as L1 adaptive control and model predictive control (MPC), adapted to the dynamics of ground effect. Their model-based cognitive control approach aims to give the craft a form of ‘self-awareness,’ enabling it to anticipate changing conditions, detect component faults, and reconfigure itself for safe operation.
The University of Luxembourg is applying AI-based flight control, using reinforcement learning (RL). To support this, digital twins of the vehicles are developed, combining available aerodynamic models and experimental data to approximate real conditions as closely as possible.
INESC TEC focuses on perception and situational awareness, fusing data from radars, LiDAR, optical and thermal cameras, and IMUs. This enables real-time modelling of the surroundings, including wave height, obstacles, and nearby vessels. By reconstructing the sea surface and traffic conditions continuously, the system can adjust altitude and flight parameters for efficiency, safety, and seamless integration with normal maritime operations.
One of the central challenges for all this work is the lack of reliable reference data. Unlike conventional aircraft, WIG vehicles have very little operational history, meaning there are no extensive flight logs or validated aerodynamic models to rely on. The highly nonlinear aerodynamics of ground effect, combined with the added complexity of waves, gusts, and low-altitude flight, make accurate modelling extremely difficult.
Market relevance and impact
WIG craft offer aircraft-like speed with ship-like efficiency, making them a potential replacement for short-haul flights and ferries, especially for islands and coastal regions. Their lower emissions, reduced noise, and minimal infrastructure needs create new connectivity options where conventional transport is limited.
TalTech University leads the assessment of economic, environmental, and social impacts, comparing WIG operations with road, shipping, and aviation. Complementing this, La Palma Research Centre (LPRC) coordinates roadmapping, outreach, and stakeholder engagement, ensuring the project informs future policy and prepares pathways toward commercial deployment in the 2030s–2050s.
Conclusion
Ground-effect vehicles have been studied for nearly a century. Past projects demonstrated their potential but also highlighted their challenges, especially in control and stability. Today, advances in electric propulsion, simulation, and autonomous systems make it possible to revisit the concept with a new perspective.
The AIRSHIP project is Europe’s effort to turn this potential into reality. By combining aerodynamic efficiency, clean energy, and advanced autonomy, it aims to demonstrate that UWV can become a practical and sustainable transport solution, filling a unique niche between maritime and aviation.
Please note, this article will also appear in the 24th edition of our quarterly publication.
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