... so an un-named power develops a nefarious plot to fly an airliner into a building, and instead of simply using a normal airframe and 300 odd knots, decides to re-develop the airframe simply in order to achieve a slightly (in terms of damage done) impact speed of 500 knots?
That's right, Checkboard, the most sinister attack ever pulled off against America was foiled by a bunch of internet pilots because the un-named planners didn't realize said pilots would figure out that it is "impossible" for a 767 to reach 500 knots at 1000 feet MSL.
Don't forget, this group of pilots also believe that the aircraft was remote piloted into the tower.