what people need to understand is this:
when a plane is going down, what normally happens?
the pilots are doing everything they can to avoid it. they are trying to minimize impact, skidding rather than nose diving etc etc.
what happened with the 9/11 planes?
the terrorists deliberately flew them into targets at hundreds of miles an hour. and in the case of the one that crashed into the ground, they nosedived it into the ground.
at about 600mph, assuming normal cruising speed.
that is a crucial difference that the conspiracy theorists don't seem to get.
this isn't the same as a pilot having to do an emergency landing and crashing/skidding into a runway.
this is flying a plane directly into a building with intent to do max. damage.
not only that, you had 110 story buildings collapsing ontop of them, literallly turning everything into pebbles.
big difference here. its part of the reason the peices of wreckage are not big and typical.