If you only have to go a couple hundred miles, the cruise speed isn't a significant factor to the overall trip time. Let the airlines handle the 1000+ mile trips (with all the associated hassles); slower airplanes don't give up near as much time on short legs.
Door to door, I can beat the airlines on most trips under 1000 miles. I don't need to get to the airport 90 minutes ahead of departure, go through security, wait for boarding to complete, wait for pushback, connect through a hub, wait for bags, and can often land at an airport closer to where I want to be and have a rental car or cab waiting. The fact that cruise speed is only 215 mph/350 kph is made up for by all the slippage inherent in airline travel.
Yes, the one thing missing that would be being able to start from a normal road, and land on something similar, which could allow pretty much door-to-door is too hard to make work for how many could afford it.
In Alaska, Montana, Idaho, North Dakota, and South Dakota, it's legal to land on rural roads.
Even in places where you can't land on roads, there are WAY more airports than you probably think in the US. It's about 19K, with a little over 5K of those being public use. (Even the private ones are often accessible with just a coordinating phone call.)
Of those, fewer than 400 are "Primary" airports (defined as having scheduled commercial service and more than 10K enplanements [commercial passengers outbound] per year).
Yes, I know there are many airports. This is about starting from "The next road with sufficiently little traffic that has suitable clearance and curvature to start from", and maybe something like folding wings inwards or so to get it small enough for maneuvering it as a large car.
Door to door, I can beat the airlines on most trips under 1000 miles. I don't need to get to the airport 90 minutes ahead of departure, go through security, wait for boarding to complete, wait for pushback, connect through a hub, wait for bags, and can often land at an airport closer to where I want to be and have a rental car or cab waiting. The fact that cruise speed is only 215 mph/350 kph is made up for by all the slippage inherent in airline travel.