I DO NOT have any 767 time. I did look at some speeds though and I'm not sure they're using the EAS correctly in their argument. (I may be wrong of course) At 2500 feet 510 KTAS is a EAS of 492 KTS, CAS of 496 KTS or 136 KTS above the 767's Vmo of 360KTS. The equivalent mach number is 0.75. No argument from me those numbers are high for an airliner at that altitude. But it's not as outrageous as the video makes it sound. I also have to consider the possibility that the pilot/hijacker ignored engine operating limits and "fire walled" the throttles. Making those speeds at least somewhat more plausible and it would explain why the 767 pilot interviewed would say a 767 could not do it. It's VERY unlikely he's ever had the throttles to the stops. I'm not sure why the narrator keeps implying the aircraft was the equivalent of super sonic at 510KTS. Mach one at that altitude/temp is around 660 KTS. Again when I see inconsistencies like this I can't help but be skeptical of THAT source.
They are exactly right in there simplistic airspeed computation example..........I myself don't have any 767 time but I have extensive experience in the B757 (aircraft used on 9/11). There have been several other military and airline pilot groups that have pointed out the same official 9/11 story airspeed fallacy.