Forgotten German Superplane: The Junkers Ju 390 and Its Vanished Legacy

In the final years of World War II, Nazi Germany poured resources into fantastical projects meant to change the war’s course. Some were desperate gambles, others genuine feats of engineering brilliance. Among them was one of the most mysterious and ambitious aircraft ever designed—the Junkers Ju 390. With a wingspan even greater than the U.S. B-29 Superfortress and six powerful engines, the Ju 390 was intended to deliver intercontinental strikes, bridging oceans at a time when aerial warfare was largely confined to regional theaters.

Yet despite its promise, the Ju 390 never entered mass production. Only one prototype is believed to have flown, before the project was abruptly canceled in 1944. To this day, questions linger: what missions was it meant to perform, how far did it truly fly, and what secrets remain buried in its short, shadowy career?

The Vision of Intercontinental Airpower

By 1942, Adolf Hitler and his high command were increasingly fascinated by what they called the “Amerika Bomber” project—a long-range aircraft capable of striking the continental United States from bases in Europe. Such missions were seen as strategically vital: crippling American industry, undermining morale, and forcing Washington to divert resources from the European front.

The Junkers aircraft company, already a cornerstone of the Luftwaffe’s bomber fleet, was tasked with developing a machine that could make the concept real. The result was the Ju 390, an enlarged derivative of the existing Ju 290 long-range maritime patrol bomber. Stretching the fuselage, adding wing extensions, and fitting six BMW 801 radial engines, Junkers engineers produced a giant with a wingspan of 165 feet—larger even than the American B-29, which would go on to drop the atomic bombs in 1945.

A Monster of the Skies

The Ju 390’s sheer size set it apart. Capable of carrying over 20 tons of payload and designed for ranges up to 6,000 miles, it represented a leap beyond contemporary bombers. With a crew of 10 and provisions for extended missions, the aircraft could theoretically reach New York City, drop its bombs, and return to occupied France.

Its airframe allowed for multiple roles: bomber, transport, reconnaissance, and even aerial refueling tanker. Had it entered full service, the Ju 390 might have reshaped the strategic dimension of the war.

The Test Flights

The first Ju 390 prototype reportedly flew in late 1943. Photographs exist of the aircraft during trials, showing its immense proportions dwarfing ground crews. Contemporary accounts suggest it handled surprisingly well for its size, though fuel consumption was a concern.

Most famously, a story emerged claiming that a Ju 390 undertook a clandestine long-range flight from France across the Atlantic, reaching within sight of the American coast before turning back. Though debated by historians—many dismiss it as postwar myth—the tale added to the aircraft’s mystique. Even if exaggerated, the very fact that such a mission seemed possible illustrated the strategic potential that the Luftwaffe hoped to unlock.

Why It Was Canceled

By 1944, however, Germany’s fortunes had collapsed. The Allies dominated the skies over Europe, raw materials were scarce, and fuel shortages crippled the Luftwaffe. Advanced projects competed for dwindling resources, from the Me 262 jet fighter to the V-2 rocket program.

The Ju 390, impressive though it was, demanded enormous investment for uncertain gain. Mass production would have diverted materials from more urgent needs, like fighters to defend German cities from Allied bombing raids. As the war turned defensive, offensive intercontinental bombing lost its appeal.

The prototype was reportedly dismantled before war’s end, leaving only a handful of photos, documents, and memories of what might have been.

Secrets and Speculation

The scarcity of surviving records has fueled speculation about the Ju 390 ever since. Some believe that more than one prototype may have been built, hidden, or destroyed before Allied forces could capture them. Others point to rumors of long-range flights to Japan, suggesting the aircraft may have served as a transport between Axis partners.

Conspiracy theories abound, too—stories of Ju 390s used in secret evacuation missions, or even carrying nuclear weapons in development by German scientists. While most such claims lack credible evidence, they reflect the aura of secrecy that surrounds the project.

What is clear is that Allied intelligence took the threat seriously. Reports of a giant German bomber with intercontinental reach worried planners, who redoubled efforts to strike German industry before such weapons could materialize.

Comparing the Giants

In hindsight, the Ju 390 stands as an extraordinary engineering achievement. Few nations in the early 1940s could have produced a bomber of its size and capability. When compared to the American B-29, it matched or exceeded many specifications—wingspan, payload, and range.

Yet there was a crucial difference: the B-29 entered mass production, with nearly 4,000 built and countless missions flown. The Ju 390, by contrast, remained a prototype, undone by circumstance as much as technology. Its potential was vast, but potential alone could not alter the course of the war.

The Legacy of the Ju 390

Today, the Ju 390 is often forgotten, overshadowed by more famous German “wonder weapons” like the V-2 rocket or the Me 262 jet. Yet it represents an important chapter in the history of strategic bombing and long-range aviation.

The idea of crossing oceans to strike distant targets foreshadowed the intercontinental bombers of the Cold War, such as the American B-52 or the Soviet Tu-95. In many ways, the Ju 390 was ahead of its time, embodying concepts that would become central to global airpower in the decades to come.

Its story also illustrates the limitations of Nazi Germany’s wartime innovation. Brilliant designs emerged, but few could be sustained in the face of relentless Allied pressure and collapsing logistics. The Ju 390 was not canceled because it failed technically, but because Germany no longer had the means to bring it to life.

Conclusion

The Junkers Ju 390 was one of the greatest “what ifs” of aviation history. A superplane with the wingspan to rival modern bombers, the engines to cross oceans, and the versatility to serve multiple roles, it might have changed the dynamics of the war had it been built in numbers.

Instead, it remained a shadow—tested, photographed, then dismantled as the Reich collapsed. The secrets of its true capabilities may never be fully known, but its legend endures: a giant of the skies, conceived in ambition, grounded by reality, and remembered today as one of World War II’s forgotten marvels.