Innovation for Cleaner Aviation – How Gliders Are Leading the Way

Gliders are the most efficient flying machines ever built—and the most advanced among them come from Germany. Aerospace engineers around the world know this well; time and again, they draw on ideas from glider technology when building their latest aircraft. Even the fast-moving air taxi industry is eager to benefit from the expertise of the gliding community.

“Vertical takeoff” doesn’t just describe a flying machine lifting straight into the sky. It’s also a phrase for any career—or breakthrough—that takes off steeply and unexpectedly. In this story, both meanings come together.

Let’s start with the aircraft. More specifically: the air taxi. To be precise, eVTOLs - Electric Vertical Take-Off and Landing aircraft. These vertical takeoff pioneers, powered by electric propellers, have been shaking up the aviation industry for several years now. Compact, agile, and full of promise, they combine the advantages of helicopters and fixed-wing aircraft: requiring neither runway for takeoff nor landing, and designed to transport people and goods over densely populated areas—faster, quieter, and more efficiently than any other regional mode of transport.

It’s a multi-billion-dollar market with around 200 startups worldwide vying for position. German companies are among them—like Volocopter from Bruchsal—alongside giants such as Airbus and SkyDrive, a Japanese company with ties to Toyota.

The air taxi sector is bursting with bold announcements, but many have proved premature. It remains a market for the future. In the short term, first applications will appear in niche markets, such as airport shuttles, sightseeing, or medical missions. The broader urban use envisioned in so many concepts is likely to come after 2030, when technology, regulation, and infrastructure finally converge.

However heavy the coffers of these startups, their aircraft must remain as light as possible to maximize time in the air. Lightweight construction is a German specialty—a field that first emerged from glider building. At Volocopter in Bruchsal, they know this well. The company was long connected to traditional glider manufacturer DG, and took over its production facilities in 2021.

The link to glider construction is no coincidence. The industry is small, its revenues modest. But its wealth of experience is invaluable. “Gliding is a success story written in Germany,” says Reiner Kickert, chair of the Association of German Glider Manufacturers and managing director of the Braunschweig-based aerospace company Leichtwerk - a name formed from the German words for “lightweight” and “factory”.

A fascination with soaring flight draws young people to universities to study aviation. Practically every aerospace company recruits from among glider pilots, including air taxi manufacturers. “Germany is the ideal location for this young industry because of its expertise in lightweight and aircraft construction,” says Kickert.

While these vertical takeoff pioneers rely on batteries and motors, allowing them only a few kilometers per charge, gliders are the true masters of efficiency. They can cover thousands of kilometers—without a drop of fuel or a single kilowatt-hour of electricity. In doing so, they set the standard for commercial aviation, which is under pressure from high CO2 emissions and an urgent need for greater efficiency.

Reinhold Messner of the skies

Which brings us to the other sense of “vertical takeoff”: a person whose rise is as rapid as it is steep. This description fits Klaus Ohlmann almost perfectly. In the gliding world, everyone knows the man with the distinctive mustache—a pilot reverently called “the Reinhold Messner of the skies.” With more than 30,000 flight hours, Ohlmann has logged more time aloft than most professional pilots. He holds dozens of world records and seven world championship titles. He flew the longest distance ever achieved in an electric aircraft - over 2,000 kilometers - reached an altitude of 12,500 meters above sea level while flying in the Andes, covered 3,000 kilometers in a single flight, and was the first person to glide over Mount Everest.

Once a dentist, Ohlmann was ultimately drawn by the call of freedom above the clouds. At 50, he moved to southern France, a glider pilot’s paradise, where he now runs an airfield. “I know every rock around here—this is my playground,” Ohlmann says.

From his base in southern France, he regularly sets out on flying expeditions around the world. When an experienced pilot is needed somewhere, Ohlmann is the one they call. More than anyone, he brings perseverance and a rare instinct for the forces of nature. "He thinks like a bird," they say. He calls it: "an accumulation of experience." Gliding, Ohlmann explains, is constant risk management. “You have to observe the weather, reassess constantly, check yourself, and adapt again and again. That’s what makes it so exciting.”

Anyone Can Fly When the Weather’s Good

On his airfield in Serres-La Bâtie, about 100 kilometers south of Grenoble, Ohlmann stands in May 2022 and scans the sky. The weather is actually too poor for flying: thunderstorms are forecast, clouds hang low, the wind is weak. “Anyone can fly in good conditions,” he says, preparing his two-seater. Riding the slope lift, he sails just above the trees, fighting his way meter by meter into the sky. Then, circling tightly in the thermals, he climbs higher. At 2,400 meters, he finally finds what he was looking for: the entrance to the leewave.

Leewaves form when wind is deflected by terrain, such as mountains. The stronger the wind and higher the obstacle, the higher the waves on the downwind side climb. Glider pilots surf these invisible currents.

Leewaves are Ohlmann’s passion. He has flown numerous records in these waves—like in 2013, when he achieved the longest gliding distance ever: 3,008.8 kilometers. He set that world record in the Andes, flying a Nimbus 4 DM from Schempp-Hirth, a glider manufacturer founded in 1935 near Stuttgart.

All of Ohlmann’s records were flown in German-made gliders. “Gliders are the most efficient aircraft there are, thanks to their construction and perfect aerodynamics,” he says. The major airliner manufacturers know this too—and look on at glider achievements with envy. Gliders achieve a glide ratio of 1:70—meaning that with 1,000 meters of altitude, they can glide up to 70 kilometers. Commercial airliners reach at best 1:20, and even then, they still burn huge amounts of fuel.

For decades, gliders have pointed the way for commercial aviation in terms of efficiency. New materials like glass, carbon, and Kevlar fiber were first used in gliders. In 1957, the fs 24 Phönix became the world’s first all-plastic aircraft. The next fiber revolution followed in 1972: the SB 10 was the first civilian aircraft with load-bearing carbon components. Commercial aviation followed in the 1970s, adopting composite materials. As with gliders, these made jets lighter and more efficient. “For decades, we were regularly 20 years ahead of commercial aviation. Now, the big aircraft manufacturers are catching up because they have to fly more sustainably to meet climate targets,” says Schempp-Hirth CEO Tilo Holighaus.

“Right now, we’re once again advancing technologically by integrating fully certified electric drives into our gliders. It works amazingly well—and we already have more than 100 fully certified examples flying, more than any other manufacturer, I believe,” says Holighaus.

Gliding Across Half of Europe

Klaus Ohlmann demonstrated what is possible with high-performance gliders on May 17, 2021. Early that morning, he climbed into his “Stemme,” an aircraft built near Berlin, and embarked on a flight that would make headlines. Next to him was not a co-pilot to take over in an emergency, but his survival gear.

For Ohlmann’s record flights, a Stemme is the perfect machine. The seats are side by side, giving plenty of space in the cockpit. There’s also an engine and a retractable propeller that extends from the nose at the push of a button. With such a motor glider, it’s possible to cover greater distances without relying constantly on updrafts. Pilots like Ohlmann can take greater risks and go further. Once the propeller is retracted, its flying characteristics are nearly identical to those of modern high-performance gliders.

A visit to Stemme’s workshop in Pasewalk, 150 kilometers north of Berlin, reveals the painstaking craft behind each aircraft. In a modest hangar next to a small airstrip, employees assemble flight-ready gliders from 6,000 individual parts—by hand. Components made from glass and carbon fiber are laminated and baked in ovens the size of living rooms. Fuselages, wings, and tails are gradually shaped, sanded, and polished for hundreds of hours—until they shine like grand pianos. Elsewhere, workers prepare wiring harnesses, install instruments, or fine-tune landing gear. Around 120 men and women work at Stemme. All this craftsmanship comes at a price: about half a million euros per aircraft. “Stemme is pure luxury in motion—a masterpiece of engineering with unrivaled performance, made for those who demand the extraordinary without compromise,” says CEO Benjamin de Broqueville.

Across the Sea

Freedom. Klaus Ohlmann values it above all. After climbing to 6,000 meters over Provence, he glided to Corsica—180 kilometers over the sea. When he arrived, his altimeter still showed 2,100 meters. Onward he went, gaining altitude again for the crossing to Italy—another stretch over water. The risk, he says, is calculated. Over the Apennines, he found, as hoped, the next leewave, which carried him along the Italian peninsula to the south. Then he dared to cross to Greece, where yet another wave carried him deep into the interior. After 13 hours and 48 minutes, he landed in Thessaloniki—having covered 1,780 kilometers.

With record flights like these, Ohlmann seeks to chart new territory—and show commercial aviation the way forward. The industry has more than just an image problem. With activists blocking runways and “flight shame” part of public debate, it is common knowledge that global aviation contributes about 3.5 percent to human-made climate change. And as more people fly, emissions will inevitably rise.

Unless, that is, Airbus, Boeing, and the rest become as efficient as the glider makers. It’s happened before: in the 1960s, composite technology made gliders more efficient, and soon found its way into commercial jets—enabling German airlines, for example, to cut fuel consumption per passenger by 43 percent since 1990. But that’s still not enough.

Aviation experts like Rolf Radespiel, former managing director of the Institute for Fluid Mechanics at TU Braunschweig, believe commercial aircraft will look more and more like gliders. “Slimmer wings, much like those on gliders, are coming to commercial aviation,” he says. In fact, Boeing and NASA have just unveiled the Sustainable Flight Demonstrator—a passenger jet whose thin, lightweight wings are clearly inspired by glider design.