Yes, you are right. There is no direct rail for many of these GA airports. What I said was:
> 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.
> 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.