The "737" hypothesis
The following diagram shows the arrival of a Boeing 737200.
The plane is figured,
at right scale, on the path where it is after having struck
the lamp poles. This axis is confirmed by the damage inside the building.
The purple central axis impacts building between pillars 13 and 14.
The two purple dotted lines correspond to the damage made to the wire
netting fence
on starboard and ventilation structure low wall on port.
They are supposed to be the paths of the two engines.
It is obvious on this diagram that the two engines of a 737200 are too close
from the centerline to account for these damage.
The yellow line touching the building's front is the extension of the damage
on the building, from pillar 8 to pillar 20. Two dotted lines have been drawn
from it's extremities, parallel to the trajectory. It seems that, if the
port wing could be supposed to have damaged the front on this extension, the
starboard cannot. But this is not an evidence:
admitting that the central axis could be shifted a little,
a 737 could be responsible of the damage seen on
the Pentagon's front. In a previous version of this web site, I even wrote
that the damage fitted exactly the size of a 737, and I was not very far from
the truth if considering that the plane kept it's structural integrity when
hitting the building. It allowed me to state the hypothesis of the "junked
737" attacking plane.
It is, indeed, reasoning at the limit, and excludes smaller
planes such as a commuter plane, a fighter like a F 16 or  still smaller 
a cruise missile.
The "757" hypothesis
Now the following diagram shows the arrival of a Boeing 757200, which is
officially the hijacked plane of flight 77.
The plane is figured, at right scale, on the same path as for the 737.
The purple central axis and supposed paths of the two engines are the same.
It is obvious on this diagram that the two engines
of a 757200 are just at the right spacing from the centerline to account for
the damage on the generator and on the ventilation structure.
...
