The wingspan of an A3 is 74 feet and in the Navy version the wings were designed to fold up for storage on an aircraft carrier (visible on the drawing above).  At a distance, painted like an American Airlines plane, this plane would easily be mistaken for a 737, 757, 767 type of aircraft because the two engines hang under the wing but are of far smaller dimensions than the 9 foot diameter jets on a 757 that not only hang under the wing but also hang lower than the bottom of the fuselage.  
 
That is an important point because there were no marks on the Pentagon lawn of those two jet engines dragging the ground and they would have based on how low the Pentagon was hit.  Said another way, forget about the fuselage dragging on the ground.  The engines of a 757 would have been plowing the Pentagon lawn but that did not happen.

http://www.rense.com/general70/safe.htm