The WindRunner is an ambitious aircraft project that could make it easier to use larger wind turbines. The company behind it, however, has never built a plane before.

The WindRunner is already being called the largest aircraft in the world, before it has even been built. But this leviathan is not being made by Airbus, Boeing or Lockheed. It is being made by a company that has never built an aircraft before.

Serial entrepreneur and aerospace engineer Mark Lundstrom founded Radia in 2016 to massively expand the size of the onshore wind power industry after he had a "eureka moment". Wind turbine blades installed offshore can reach 100m (345ft) in length – or more – much larger than those on land which tend to be only around 70m (230ft). This is due the difficulty of transporting something so large from the factory to a remote site on a plain or plateau. This in turn limits the economic viability of onshore wind power.

If this problem could be solved, Lundstrom thought, then the longer blades would help onshore wind farms to produce more energy at a lower cost. "They can double or triple the economically viable land in the US for wind farms," says Lundstrom, and could enable the building of over one million of these "super" turbines by 2050, globally. The entrepreneur calls his vision "GigaWind".

Now the company based in Boulder, Colorado has raised more than $150m (£110m) and attracted high-profile advisers to launch a possible solution: the WindRunner. The largest heavier-than-air machine in history is designed to make the transport of huge wind turbine blades a great deal easier and, Radia claims, trigger a revolution in onshore wind power.

"We are building the world's largest aircraft and we're doing that because there's a gigantic gap in the capability of heavy-lift aircraft," says Lundstrom, the company's CEO and founder. "It amazes me that there is no large cargo aircraft in production or planned to meet this need, except for the Radia WindRunner.

"It's the inability to move big things that is basically the barrier that prevents us from super-sizing onshore wind turbines," he says.

There is one additional challenge. This huge machine must be able to navigate the runways and taxiways of existing airports as well as operate on the types of relatively short, semi-prepared airstrips that can easily be built next to wind farms.

Such outsized giants have a precedent. The huge six-engine Antonov An-225 Mriya ("Dream" in Ukrainian) cargo plane used to be the world's biggest aircraft. Its cargo hold was longer than the Wright Brothers' first flight, from take-off to landing. But it was the only one its kind ever completed. Its destruction during the first stages of the Russian invasion of Ukraine in 2022 was a symbolic blow to Ukraine, and a literal one to the world's aviation community. Overnight, the ability to transport extremely large and oversized cargo – whether complete railway engines, wind turbine blades or disaster relief – was lost.

What's more, the An-225's one-time rivals in the strategic airlift category, such as the

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