[IncPen]

Actually, right after 9/11, some federal agency (maybe the NSA) announced that they had calculated that the velocity of the planes + the fuel = a 20 megaton device and thus, for crimes-against-humanity-in-the -world-court-reasons, they were Weapons Of Mass Destruction....

[BohDaThone]

20 megaton would have vaporized the whole south end of Manhattan, at a minimum. Maybe someone said 20 kiloton, but I would guess that 1-2 kiloton would be more realistic. Remember, 10-20 kiloton killed c. 80,000 at Hiroshima.