Only thing I've heard about that is something was launched from the roof of the Sear's tower. No doubt it was for effect only, to give the appearance of the Marvin_Bush-Security-Firm/Controlled-Demolition-Inc rigged towers being hit by an aircraft.
The mid-air pulverization was compliments of Brookhaven National Labs. Check the line-of-sight on the side of the towers with melted auto wheels.