Re: Two sides to the coin
Lots of fleshy targets in the planes and in the buildings - they could have caused much more disruption had they dropped the planes onto, say, 3 Mile Island or into the Hoover Dam,
You are missing a key point here. This is documented with Osama saying that he had no clue what the damage will be, if he had he may have chosen targets differently.
First of all, let's go back to the roots. The 9/11 "idea" was a plan originally by Dudaev as a part of his "freedom campaign" against Russian "soft" targets. It was planned differently - with trainer aircraft packed with explosives. He "bought" (or had them donated) a large number of trainer aircraft from the Baltics and several other NATO countries (*) He intended to use his intimate knowledge of the Russian AA defenses which he flaunted regularly by flying from Chechnia across Russia to the Baltics and back undetected to bring them to targets(**)
The satellite photos of the fleet in question at Hankala are in the public domain. Similarly, photos of what was left of them at Hankala after the first battle for Grozny is also in the public domain. Dudaev never managed to execute on his plan as he could not get enough suicide pilots in time (the fact that any candidates knew that their esteemed leader will be coming back and they will not probably had something to do with it). A number of Saudi mercenaries who fought in that war as well as a number of Chechens went to join Al-Qaeda after that and the rest as they say is history.
A trainer aircraft or even a larger prop aircraft has a very different impact profile. For example when a B25 collided with Empire State during the war, the damage was minimal: https://en.wikipedia.org/wiki/1945_Empire_State_Building_B-25_crash
The change to jets done by the 9/11 attackers was only a month before the attack and only because they could not source enough trainer aircraft. They did not have a clue of how the damage profile changes when a jet full of aviation fuel hits something.
So if they knew what the result would be the might as well have hit Three Mile island. They did not.
(*)I am leaving the question of how can you buy 50+ trainer aircraft while involved in a war without assistance from the country in question as an "exercise to the reader". Similarly, I am leaving as exercise to the reader did Dudaev come up to this idea himself
(**)Supposedly. There is an alternative rumor that it was all show for propaganda purposes and he actually flew to Sofia in Bulgaria first every time and then north.