Crash wreckage
First of all let's get one thing straight, when a collision occurs it doesn't matter which object is moving faster:
So this is how aeroplanes generally respond to impact:
Look how the nose crumples:
Notice the strength difference between thin steel and aluminium sheet:
And at higher impact speeds things look like this:
Now have a look at how tough steel is:
Look at how an aircraft is constructed:
This train hit a steel post:
And look at what the outer wall of the WTC was made from:
Notice that a lot of the surface area is steel.
These are not thin, blade-like columns. and the spandrel belts are wide:
This was structural steel.
And of course where the spandrel belts were, there were poured concrete floors.
So this image, for instance is not possible in reality:
The following simulated image, though not correct, is much more like what would have happened:
