The Airport Fence

Perhaps it's just a reflection of a more general distribution of wealth.
Those who can easily afford to fly may be the wealthy urbanites with good
professional jobs, whereas rural populations may have lower average incomes
and thus might not be able to easily afford flying.

This is certainly my theory and impression, but I have only my
observations to support it, no real data.

As to why aircraft sit and rust, I'm not sure. Maybe people get over the
"honeymoon" period of being new pilots and then lose interest. Or maybe the
expense makes it impossible for them to keep up with flying, and they
gradually forget about it.

You underestimate the fundamental and visceral pull of aviation to
most pilots. It goes far beyond the rational.

My counterpoint would be, for those cashing out the only logical
solution would be to sell the aircraft, even for scrap. I cannot
imagine many people "forget" the 30-120 dollars a month they pay for
ramp space. There is absolutely no economic value to an aircraft
rotting on a tarmac, if they have merely 'lost interest', then
obviously they should get whatever capital they could back out of
their investment, or at least temper their loss.

Instead, when I see an aircraft rotting on a flightline, what I see is
hope. Someone who can no longer afford to fly, but hopes against all
rationality that "some-day" their circumstances will improve and they
can return to the air.

Thus, to me, aircraft sitting on a flight line are indicative of the
financial state of the local flying population, rather than a
testament to their collective interest in aviation. If they lost
interest, they planes wouldn't be on the flight line any further. The
fact that they're still there indicates that the interest remains, but
the ability has faltered.

Are these rusting aircraft just at the rural airports, or are they at other
airports? Maybe it's just cheaper to let an aircraft sit at a rural airport,
whereas it might be expensive at a larger GA airport where you have to pay a
lot for a place to park whether you regularly fly or not.

This is certainly a fair point. I know there are a great deal more
derelicts sitting on the HWD flight line than there are on the SQL
flight line, 60 and 115/month tiedown fees respectively. (The
airports are otherwise a mere 5nm from each other, although SQL sits
in a far more affluent part of the region). In either case, we're
talking a tiny fraction of the total aircraft on field, no where near
the levels you'll find at some of the region's rural airports.

I'm sure its some combination of the two.

Somehow I find the image of a little plane sitting in the weeds and rusting
away to be very sad. Ready and willing to fly, but nobody wants to take it
out for a spin.

Either neglect or naive hope in the face of simple financial reality,
it is a tremendously sad thing to witness, I agree.