The official report by the National Transportation Safety Board (NTSB) relating to the two planes that crashed into WTC on September 11, 2001 shows that they were traveling at a speed of 945 km/h and 796 km/h respectively.
Pilots for 9/11 Truth, an international organization of pilots and aviation professionals, has pointed out that, according to the manufacturer, the Boeing 767 develops structural failure and dismembers at a speed surpassing 660 km/h when flying at near sea level in thick air. This has also been certified by a former senior NASA executive, Dwain Deets.
It necessarily follows that the aircraft that slammed into the World Trade Center could not have been the planes corresponding to commercial flights United 175 and American 11.
In his book The Big Lie, Thierry Meyssan had entertained the possibility that the two aircraft had actually been substituted by military planes according to the procedure contemplated in Operation Northwoods (p. 168).
The NTSB report, which was declassified at the request of Pilots for 9/11 Truth, had already revealed that the cockpit door of flight American 77 had remained locked from the time of take-off until it disappeared from radar screens and allegedly crashed at the Pentagon site. The logical conclusion is that it would have been materially impossible to highjack the flight.