Cars/trucks, diesel-electric or electrified freight trains, diesel ships, jet planes, electrical wires, and pipelines, (and tracked vehicles, helicopters, nuclear subs, rockets, cable railways, etc. in niche roles), are practical means of transportation given our particular available resources, history of infrastructure investment, etc., but they are familiar and boring to make a speculative fiction story about.
Coming up with an alternative set of constraints where other kinds of transportation (zeppelins, space elevators, pneumatic tubes, conveyor belts, ornithopters, futuristic sailboats, teleporters, ...) are economically/physically viable is fun for authors and readers.
Definitely! There's a fun YA trilogy by Kenneth Oppel called Airborne that takes place in an alternate-history midcentury where heavier-than-air flight has never been invented and people cross the ocean in giant airships.
He also invents some other stuff like the gas "hydrium" (non-flammable, much more bouyant than hydrogen) as a plot element, and that also helps sell the overall practicality of airship travel. But yeah, it's a good read-aloud to kids or even just a quick one for yourself, similar to something like the Hunger Games.
Now I'm imagining some sort of steampunk multiverse tour guide character popping into our universe with a bunch of customers, like "And here we see the local-minimum zeppelin universe. Notice how, due to the fact that their flying vehicles are heavier than air, they've isolated them to areas outside their cities for safety! They call these 'air-ports.' Yes, like a regular port, but for the air!"
I dunno, in a hypothetical world where massive balloons had had as much R&D put into them as a modern aircraft, they maybe they can use the loitering advantage to make skyscraper landings possible. Anyway, these travelers come from a steampunk universe, so theirs are probably unrealistically capable.
If only Earth had, say, 1.5x the atmospheric pressure and two thirds the gravity. Lighter-than-air vehicles could be super feasible (but so would heavier-than-air ones!)
Zeppelins could be absurdly useful on Titan as well as the upper atmospheres of Venus and even the gas giants.
Actually wouldn't it be the other way around with gravity? Higher gravity would make planes less practical while airships don't care because their lift comes from buoyancy that scales with gravity.
That said, thicker air would also mean more lift from wings, wouldn't it? And more drag for the massive cross-section of an airship.
Two thirds the gravity, so thicker air and less gravity is what I meant. Gravity doesn't affect buoyancy, but it does affect the weight of the payload. Lower gravity means you lift more stuff with the same buoyant mass, right? And yeah, thicker air would mean more drag, but also more thrust from the engines.
Wouldn't gravity affect buoyancy? Since buoyancy is caused by the heavier substance flowing under the lighter substance and pushing it upwards, wouldn't higher gravity mean higher buoyancy, and therefore the lifting power vs payload would be a wash?
In fiction, alternative universes always have more zeppelins.
(It's actually one of the most common ways to visually signal "alternate timeline").