With regard to the Grand Canyon, I must admit I am of mixed opinions
because I am a pilot, but also spent summers out there (in the early
90's) in college working with the National Park Service Resources
Management office, and specifically also the pilot who is the NPS
point person on this issue. The NPS pilot who worked on this project
is one of us (ie a general aviation pilot who flew for the park and
also owns a 172), and you can meet him at the NPS stand in the Federal
Pavillion at OSH, he has been coming to OSH for quite a few years now
and can explain all the history behind this far better than can I.
It is VERY controversial.
The air tour business had gotten so busy, and so intrusive (to MANY
people) that the Park Service had to intervene with the help of the
FAA, and in response to the dramatic increase in air tour business
over the Canyon. Some structure had to be placed to bring order to the
business, and hence we have the regulations as we see them now. The
corridors that you see on the Grand Canyon special use VFR map (which
looks like a detailed sectional or terminal area chart) is in response
to the HUGE number of complaints about how the air tour business was
conducting itself, it was essentially a free for all. They were not
really aimed at us, the occasional VFR pilot flying a Cessna, but we
get lumped in as well. If you spend any time beneath any of the VFR
corridors, you quickly get a sense of how busy it really is. A
constant stream of Jet Rangers, Twin Otters, and other aircraft flying
the tours that quickly makes the noise issue very paramount. The VFR
routes over the canyon bring some structure to the mess, and was
really needed as the traffic count was climbing quite dramatically. It
would be the same if there were no Ripon-Fisk arrival at OSH, so one
could very reasonably argue that it is a safety issue as well.
The wreckage of the Connie and DC-4 (if I remember correctly) at the
bottom of the canyon can attest to that.
Flying below the rim is spectacular, but not for the faint of heart.
It is basically an inverted mountain, so all the warnings and
recommendations for flying to the back-country strips in Idaho or
flying over the mountains out west would apply in spades at Grand
Canyon. So going for a spin down in the canyon might be fun, and you
probably would get away with it (no radar), but wouldn't necessarily
be smart.
I used to hike extensively in the Canyon, and I can say that even
though I am a pilot, there is something to say about visiting a
national park and NOT having the noise of the constant stream of Jet
Rangers and Twin Otters flying overhead. That means ALOT to ALOT of
people. I wouldn't be so quick to label them "noise nazi's" when you
are talking about one of the crown jewel national parks in our
country. It's not like the dimwit who builds his house next to the
airport that has been there for many years (a problem I encounter at
my local airport C29, and they ARE noise nazi's!).
So that is my perspective, both as a pilot and someone who worked at
Grand Canyon.
If you want to learn more, meet me at the Federal Pavillion in July at
OSH.

-Ryan in Madison