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Why a Climate Startup Is Building the World’s Biggest Airplane

Inside episode nine of Shift Key.

A Radia Windrunner.
Heatmap Illustration/Radia

Radia is a $1 billion climate tech startup with an unusual pitch: It is trying to build the world’s largest airplane. Its proposed aircraft, the Radia Wind Runner, would be as long as a football field, nearly as wide as a New York city block, and capable of carrying 12 times the volume of a Boeing 747. Such a plane could ferry massive wind-turbine blades, unlocking what the company calls “gigawind” — the ability to build offshore-sized wind turbines on land.

Why is that important? Because the larger the wind turbine, the more electricity that it generates — and the less wind it needs to work with. Radia says that its “gigawind” farms could profitably go into places with slower wind speeds, such as the Northeast or Mississippi Delta. They could also be built in the existing Wind Belt, potentially doubling current output.

In this week’s episode, Rob and Jesse talk to Radia’s chief executive officer, Mark Lundstrom. (Jesse’s consulting firm did some research for Radia while it was in stealth mode, in 2020 and 2023.) We discuss why the world needs a bigger plane, how such a new aircraft gets licensed, and why massive wind turbines could be such a big deal for renewable electricity. Shift Key is hosted by Robinson Meyer, executive editor of Heatmap, and Jesse Jenkins, a Princeton professor of energy systems engineering.

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Here is an excerpt from our conversation:

Jesse Jenkins: I’m here in the mechanical and aerospace engineering department at Princeton, so we’ve got a lot of students excited about new aerospace applications. I have a six-year-old kid, as well, and he’s also excited about anything that goes fast and is big, so I’m sure he’ll get excited about the eventual Lego kit for the WindRunner that we’ll have to get out in the world. But talk through the size of this aircraft compared to, say, something we’re used to, like a 737 or more conventional aircraft.

Mark Lundstrom: Sure. So before understanding the size, one has to understand the fundamental mission requirements. And so the goal, Radia’s goal is to be able to move up to a 105 meter long object that could weigh up to 75 tons. Now we can also move multiple smaller blades, so two 95s, or three 85s, or four 75s. So the vehicle is quite versatile.

In terms of sheer size, it’s about 12 times the volume of a 747. So it’s very, very large compared to the 747. It’s about nine times the volume of the Antonovs. And yet what's very different about it —

Jenkins: And the Antonov, that’s the largest plane built to date, right?

Lundstrom: Yes, the largest volumetric plane right now. There’s about 14 or 15 of them left in the world, usually Russian or Ukrainian operated.

Robinson Meyer: I was going to say, I remember the biggest plane in the world being destroyed right at the beginning of the Ukraine War and was wondering how that compared to the to the WindRunner vehicle.

Lundstrom: So the Antonov 225, there was one of them. WindRunner is six times bigger in volume than that airplane was, and it’s nine times bigger in volume than the remaining Antonov 124s that are still out there. And so, and what’s additionally unusual about it, in addition to the size, is its ability to land on dirt.

Meyer: Wow.

Lundstrom: Things like Antonovs, 747s, etc., they need to land on about 9,000 feet of steel reinforced concrete, typically. And we designed the WindRunners so we could land on relatively short dirt strips, so just over a mile of a semi-prepared field. And that allows us to bring the payload into a wind farm, and be able to get a very large aircraft out of the wind farm. It’s probably the first time that an aircraft has been designed to optimize around volume, as opposed to mass.

Usually when an aircraft design team starts off, they’ll start off thinking about how much mass has to be moved. We really started off thinking about how much volume has to be moved. So there are aircraft that move larger mass than the WindRunner. There’s absolutely no aircraft that comes close to moving larger volumes and being able to land that volume on a relatively short dirt strip.

This episode of Shift Key is sponsored by…

Advanced Energy United educates, engages, and advocates for policies that allow our member companies to compete to power our economy with 100% clean energy, working with decision makers and energy market regulators to achieve this goal. Together, we are united in our mission to accelerate the transition to 100% clean energy in America. Learn more at

KORE Power provides the commercial, industrial, and utility markets with functional solutions that advance the clean energy transition worldwide. KORE Power's technology and manufacturing capabilities provide direct access to next generation battery cells, energy storage systems that scale to grid+, EV power & infrastructure, and intuitive asset management to unlock energy strategies across a myriad of applications. Explore more at

Music for Shift Key is by Adam Kromelow.


Robinson Meyer

Robinson is the founding executive editor of Heatmap. He was previously a staff writer at The Atlantic, where he covered climate change, energy, and technology. Read More

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