America is too big for planes, too. If your transportation solution is flying, now everyone has to get around via endless highways or big, complicated regional airports, and you can only have so many of those. There's a reason why rural areas in North America have completely different politics from urban areas, and why so much of it is driven by a sense of isolation and abandonment. Trains promise to help here because they are able to stop in small places that will never, ever have practical airports.
A good rail network provides a reliable, consistent, repeatable, and straightforward three hour connection from Nowheresberg to the nearest city. Slow, but good enough to feel like they exist in the same planet. Unfortunately, that promise is subtle, and it plays out over decades, so the reward system we've created for ourselves is incapable of supporting it. And thus, we have Amtrak and confederate flags
Rural America is covered in local airports. No large commercial carriers, but the airports exist.
We need more rail. The argument starts from a bad premise.
They're not viable as general passenger hubs.
Why not though? Honest question, I've been to an airport that had a terminal of around 30 square metres with decent passenger service in the EU.
I'd say it's the flying that's not scalable, not the airport footprints.
Most municipal airports can't handle jet engine planes around here. They are all just small body, single engine aircraft on poorly maintained and non-level runways. They are fine for recreational flights, crop dusters, or flight instruction, but most rural airports here are little more than a few hangers and an administrative building with a runaway.
So the airport I'm talking about is Sønderborg, it also can't service jets, the only passenger service operates 2-3 twin turboprop planes to Copenhagen and back. The airport is six hangars, the terminal literally is a single room with enough room for the passengers of a single plane.
I can see how small airports would make sense in Denmark since the landscape of islands and peninsulas makes direct paths by road or train nearly impossible. I'm in Ohio, which is comparable to Poland in geography. Rolling plains along a smooth coastline in the north with sizable hills and low mountains in the south. Flying from Toledo to Akron doesn't make any sense since driving that is less than 2 hours, and so passenger rail would be a mich better option. You barely even see commercial flights from Cleveland to Cincinnati since the driving distance is doable for a day trip. A rail line connecting Cleveland, Columbus, and Cincinnati would be perfect for us instead of lots of tiny airlines.