in commercial it is easier to argue that efficiency gets you something looking a lot like the DC3 or the Ju52 or the Constellation. Passengers over distances sets parameters that might be met with different product from different firms
That's true to a point. I'd suggest, given
Hindenberg doesn't wreck airships, the market for large heavier than air may be pretty small. Even flying boats are up against the lower cost of operating airships. Which makes me wonder what the "floor" for commercial survival is, in that circumstance: it's unlikely OTL's 21 (DC-3) is high enough. Is it 30? 40? More? So is the *DC-3 more like the DC-6 or Connie?
Does it mean a cleavage between airships & aircraft on speed? That is, fast executive aircraft, like DC-8s & (maybe) Cessna 500s, for business travel, & airships for tourists. Could that push as far as successful SSTs?
It's pretty obvious there would be many, many fewer airports with much, much less concrete. Terminals to accommodate many more passengers might be credible.
Consider something else: what does this do to general aviation? Does this mean Piper, Cessna, & others never happen? Does it mean the J-3 Cub & 152, frex, never even fly? Or aren't a big success? Does it mean there are airship equivalents? If it does, any thoughts on who builds them?
It also occurs to me, heavier than air might be much less safe than OTL, with fewer aircraft in the game.
It also seems very probable the competition would be a lot better: a lot more variety of companies trying to get a performance edge. And the variety of designs might be greater, too: a kind of "commercial combat" offering opportunities, where even slight gains make a big difference--for heavier than air, anyhow.
Aeroengine technology is likelty to be better in that environment, too, for both cost of operation & noise reasons. It would have to be.