Were the terrorists flying all the time ? Is it that hard to hit a building?
John Lear maintains that VMO is an absolute aerodynamic limit on the airframe above which flutter would prevent novice pilots performing the manouveres.
Want to point out that the plane was flying low, 100 ft. and less at 530MPH, cruise speed for the 752, no excessive anything but stupidity. It seems like it dived and levelled some then crashed.