The balloons of most modern airships are filled with helium rather than the explosive hydrogen used in the Hindenburg. Concentrated helium is lighter than air, and when divided into gas sacks, the vessel can stay aloft if any are breached while propellers powered by flexible solar panels can help navigation.
Extracting enough helium fuel will be energy-intensive, and there’s a looming global shortage. Luckily, advances made since the Hindenburg now allow airships to fly on cylinders packed with hydrogen jet fuel, which is cheaper, lighter, and relatively abundant.
Using hydrogen for fuel has become a lot safer since the 1930s—so much so that it’s now being considered for use in the home. Unlike jet aircraft, once airships are aloft they don’t need lots of energy to keep them there. At that point, the energy costs become comparable with rail travel.
Airships won’t get passengers to their destinations very fast—the Hindenburg set the current record for a transatlantic crossing at just under 44 hours—but they do allow time to enjoy stunning vistas. Think of them instead as air cruises. In the romantic era of early commercial flight, airships were expected to become “flying hotels” that could accommodate dining rooms and ballroom dances.
There’s one more option, but you might struggle to believe it’s possible within the next 30 years. Still, the materials needed to build it already exist. An orbital ring is a strong steel cable in orbit just above the atmosphere—50 miles above Earth. It rotates, creating forces that try to make the ring fly apart into space, while gravity tries to pull it down to Earth.
If the ring is spun at the correct speed, the two forces balance one another, allowing it to rotate seemingly weightlessly. A “cuff” can be built around the cable which would hold itself in place, unmoving, by magnetic repulsion. The structure would be connected to the ground by cables, with an elevator giving access to the ring in less than an hour.
How we’ll travel in 2050 – Fast Company