I fly between Helsinki and London often enough. On that route, the aircraft is typically either an A320 or an A350.
The size of jet planes is dictated by fuel cost. Fuel is expensive. Large planes expend it more efficiently. But they are also loud and pollute. So people don't like them too close to where they live. When you use fuel by the thousands of liters per flight, it starts to add up in terms of cost. It's also why private jets are only for rich people. They burn hundreds of liters of expensive fuel per flight. Add to that the maintenance and staffing and you are looking at eye watering amounts per flight.
Hydrogen is of course not cheap currently but it might drop in price substantially as renewable energy gets cheaper. At that point a few smaller planes might be cost competitive with a larger jet fueled plane. But still, there are lots of logistical challenges related to getting large quantities of hydrogen to fuel planes. I doubt it will be very economical or practical any time soon.
My pet theory is actually that most short haul flight will shift to small, autonomous, electrical planes. They'll wipe out three of the largest cost factors in aviation: fuel, staffing, and maintenance cost (much less complex mechanical systems). They'll fly point to point rather than hub to hub; or at least tiny airport close to your origin to tiny airport close to your destination. If you want to fly further, you can just chain a few hops. It will work like an uber pretty much.
Inter continental flight is a different challenge. At least short term it's not feasible to do that with battery electric. Synthetic fuels and hydrogen look promising for that. But I wouldn't discount electric for that either long term. If battery breakthroughs keep on happening and we get some fancy solid state batteries delivering 2000 watt per kg or so, that whole game changes as well.
If you use GA airports near more prominent cities, using rail transit to get to nearby larger cities is worth the disruption. For example, with these aircraft, BED would have enough traffic to Boston to justify an extension of the Red Line through Lexington and Arlington.
This aircraft isn’t very big. These types of regional puddle jumpers are only useful when connecting to major long haul aircraft, which is only really possible at large airports.
> justify an extension of the Red Line
It's obvious that even with small electric aircraft, there would not be enough traffic to justify the expense of rail expansion. However, point-to-point air flights would increase the economic viability of many small cities without the need for hub airports. For example, I was driving for business for a while to Burlington, Vermont. I would have welcomed a small puddle jumper from the GA airport 5 miles away to Burlington instead of having to drive to fly out of Logan. It would've been more expensive than driving, but it would have been more enjoyable since I'm the kind of passenger who leaves nose prints on the window. Flying from a local airport to Ithaca, New York (partner's family) would be a viable replacement for driving 6+ hours.
Many more possibilities become practical once you free yourself of the hub and spoke model and combine it with economical electric aircraft.
Highway self-driving is going to come. And highway self-driving will probably replace the regional flight. If I could sleep in my car to get where I was going while I drove me on highways overnight, it would probably replace all airline flights less than 800 mi and probably more.
You get to leave whenever you want. You got to take a far larger amount of baggage. It gets seriously cheap for a family. You can stop away along the way to rest. The seats are more comfortable. And when you get there you have local street transportation. No need to rent a car.
A self-driving RV van and the sprinter class or something like that makes it even easier.
The solution here is adding more automation and moving away from the way things have been done in the past century. Ultimately, the congestion has more to do with pilot and controller situational awareness and stress levels than with the air actually being congested.
As for physical places to land, that's a much easier problem to solve. Vtols basically need a glorified parking or some kind of field. Small planes need short runways. 3000 feet would be plenty for a lot of those. Less possibly.
PAE in Seattle has so many restrictions because airports are terrible neighbors, despite the clear demand for more than just SEA.
* Short-haul flights, which often compete with cars and trains. Those could be plausibly served by electric VTOLs. If the claims about noise levels are true, the terminal does not need to be much larger than a city block.
* Medium-haul flights, like discussed here. The aircraft need to be much faster than the VTOLs proposed so far. Conventional runways seem to be necessary for efficiency, but they could be shorter than today.
* Long-haul flights that need big planes and long runways.
Airports that need runways are problematic, because the economic value they provide is low. There are often other more valuable uses for the land. In big and even not-so-big cities, airports tend to move away from the city over time.
For example, Helsinki recently closed the Malmi general aviation airport, which was conveniently located ~10 km from the city center. The area surrounding the former airport is now being developed as a medium-density residential area for 25k people. The runways were not long enough for current regional aircraft, and the facilities and the transit connections could not handle a meaningful number of passengers. As the alternate use as a residential area was worth billions, the airport could no longer be justified.
Instead, a huge problem with aviation is making flights between smaller cities viable. If the OP's planes get any lower operational costs or can profitably scale into fewer passengers, his company will have plenty of success.
Atlanta for example is a huge busy airport but also serves a lot of regional connections. I have flow in on a 757 and transferred to a much smaller regional jet to hop to a smaller city or town.