Airships are a concept which is inherently attractive given their theoretical simplicity, but highly impracticle on closer examination. They're not impossible, but they're far less viable than would first appear.<p>Heavier-than-air powered aircraft were largely a result of powerful engines and energy-dense fuels. Emergence of mass-produced automobiles and the first aircraft occurred within a few years of each other. Materials science (duraluminium) was another major factor. Aeronautical engineering was largely secondary and likely would have emerged with experience regardless.<p>For airships, the key enabling factors are lifting gases and materials, in this case the gas-bag envelopes. For early-20th-century airships, the material of preference was ox intestines, glued together. One airship required the entrails of ~800,000 oxen.<p>See EngineerGuy’s video (accompanies his book) on the doomed British Airship R-101:<p><a href="https://youtube.com/watch?v=ixxXhZVFXxQ" rel="nofollow">https://youtube.com/watch?v=ixxXhZVFXxQ</a><p>There are some factors which might help, and others which still work against, airships.<p>Rather than hydrogen, a "hot helium" design might offer greater flexibility. There's actually some research of such concepts: <a href="https://ui.adsabs.harvard.edu/abs/1987STIA...8748646R/abstract" rel="nofollow">https://ui.adsabs.harvard.edu/abs/1987STIA...8748646R/abstra...</a><p>Materials science might allow for improvements in gas-bag design. Plastics made mid-century blimps possible, and modern Zeppelin semi-rigid airships rely on PVF (polyvinyl fluouride), principally. Graphene or other monatomic sheet materials might allow for thinner and/or stronger designs.
Similarly structural components (frames, guy-wires) might benefit by both materials and computer-aided design and improve mass:volume ratios, safety margins, maintenance requirements, or other factors.<p>Improved lifting gas properties or mixes might also be an option, though here chemistry is fundamentally limiting.<p>Integrating PV capabilities into an outer skin might reduce fuel requirements, though even covering <i>all</i> the top surface of a USS <i>Los Angeles</i> sized airship (200m x 30m) would provide less than 300 kW of power. The Zeppelin NT (70m x 14m) has 3x 150 kW engines (450 kW total). Routing electricity next to hydrogen gas bags might prove problematic.<p><a href="https://en.wikipedia.org/wiki/Zeppelin_NT" rel="nofollow">https://en.wikipedia.org/wiki/Zeppelin_NT</a><p>In all, I expect materials innovation might contribute to fractional improvements in airship capabilities or aspects, but not improvements of multiples.<p>Note that airships also have the submariner’s problem concerning buoyancy: lift is proportional to volume, but volume varies with pressure. As a submarine descends, there’s additional pressure on its buoyancy tanks, compressing the gas within them, reducing buoyancy further. As a submarine sinks, it wants to sink further, which may prove interesting if crush depth is exceeded. (Destin Sandlin’s recent “Smarter Every Day” series aboard the USS Toledo is pretty fascinating in this regard.) By contrast, in an airplane, lifting forces <i>increase</i> as one descends, and <i>decrease</i> as one ascends.<p>For airships and balloons, you’ve got the reverse problem: as they rise, the lifting gas expands. After a point one of three things must occur: the gas is vented (and lost forever), the envelope expands, or the gas is pressurised (meaning carrying the additional mass of compressors and pressure vessels).<p>One of the biggest disadvantages of airships compared to jet aircraft is that jets fly <i>above</i> the weather, at 30k--40k feet, whilst airships fly <i>in</i> it, often at only a few hundred feet altitude. The Hindenberg’s cruise altitude was 200m (650 ft), see: <a href="https://www.airships.net/hindenburg/flight-operations-procedures/" rel="nofollow">https://www.airships.net/hindenburg/flight-operations-proced...</a> Operating and flight ceilings of 16k and 21k feet were apparently possible. Passenger Zeppelins were unpressurised. Note that this makes crossing even relatively low mountain ranges a challenge. Given the large number of airship failures in which wind and weather were primary or contributing causes, this is a major handicap.<p>The altitude record for an airship is 95,000 ft, though that’s for an unmanned system consisting of little more than the lifting balloons, frame, and propulsion. <a href="https://newatlas.com/highest-airship-flight-record/20379/" rel="nofollow">https://newatlas.com/highest-airship-flight-record/20379/</a><p>High-altitude flight requires a pressurised passenger compartment (increasing costs and risks), supplemental oxygen (the jet airliner's air-bleed pressurisation system is not available), and other factors.<p>The other massive disadvantage is that airships serve a limited number of roles and compete poorly against alternatives. They're highly intermediate between heavier-than-air airplanes and ships. They lack the former's speed (115 kph vs. 1,000 kph), and the latter's cargo capacity (160 tonne vs. 210,000 tonne for a Triple E-class Maersk container ship). Overland, airships would have to compete with river and canal traffic, rail, and trucking. The remaining remote-location work is likely of relatively limited economic value.<p><a href="https://en.wikipedia.org/wiki/Triple_E-class_container_ship" rel="nofollow">https://en.wikipedia.org/wiki/Triple_E-class_container_ship</a><p>That leaves the prospect of intercontinental trans-oceanic voyages, probably largely passenger and high-value cargo. Airships are likely to be limited to ~100 -- 200 kph. A transatlantic trip (NYC-LON) would take 1dy 4h to 2dy 8h. A Los Angeles -- Shanghai trip would be 2--4 days. Los Angeles to Sydney, 2.5--5 days. Given no other options, I could see that happening, but even a drastically curtailed fuel-based airliner industry would likely be preferable. Given either a carbon offset, synthetic hydrocarbon analogues, or carbon-neutral fuels, this seems more likely.