Methinks it\'s a hoax. In a city like New York where there are endless numbers of tourists, workers and residents walking around, there must have been others who saw it, not just in the towers themselves, but people on the ground.
I cannot believe that the people in the helicopter were the only ones who would have witnessed it.
I don\'t know how thigs work in New York, but it stikes me as incredibly convenient that they were in the right place at the right time with a TV camera, as well as a digital camera.