Just jumpin in to open up some more discussion...
I imagine mostly all of you are fighting to prove that 9/11 happened the way the govt says it did, so I'm not going to fight with you all. First I'd like to insist that you pull off of the John Lear bashing a little and concentrate on the aspects that bring him to his conclusions. Maybe exceeding VMO won't "bend wings" or cause "flutter." I don't know, never tried it... and if I did I certainly wouldn't admit it (looks around for FAA inspectors hehe), but going off of the structural damage that could be caused by an overspeed condition, maybe we could converse about how Center of Pressure (Lift) moves over the upper camber of the airfoil as speed is changed, especially in a swept-wing aircraft. I may be really tired right now and forgetting something, but I know this is where the term "Mach Tuck" comes into play. Also for you all talking about how jets fly up near MMO at cruise... OF COURSE THEY DO. What is the point of spending all that time and fuel (money) to climb to say FL350 (meaning 35,000 feet). Its definately not for the view! Air is thinner at altitude. As air thins, there is less resistance and the aircraft can penetrate the air with much less energy required, therefore giving you a faster ground speed. This is also why those "v speeds" are so much higher at altitude (minus the fact that there usually are no birds up there either, in the case of the 757). Also we have a problem called "Coffin Corner" at high altitudes... which comes from how the speed of sound (Mach) decreases and stall speed increases with altitude. It's a tiny window of airspeed that the pilot must stay within. Blow it and you're done. The higher you go, the smaller the room for airspeed fluctuation. Slow down too much, you stall the aircraft, speed up too much and you overspeed, which then results in "Mach Tuck." These are some reasons why jets fly near MMO all the time at cruise. Time and Safety. By climbing to high altitudes and flying fast, the jet is saving time and money and providing safety by keeping the aircraft away from a stall at altitude.
What about Parasite Drag at Sea Level vs FL350? At Sea Level, the very dense air going into the Pratt & Whitney 4062 turbofan blades would cause a lot of air to get jammed up like a dam at the engine inlet, in turn causing massive amounts of parasite drag. Throttle setting would also be a factor in this discussion... More throttle, more air being used, (less parasite drag?), less throttle, less air being used, (more parasite drag?). Also, there is such a dense amount of air going into the compressor section that the combustion would be hotter and faster, in return spinning the fans faster and causing detrimenal exceedances on the N1/N2 RPMs and Tempurature limits, which would then blow the blades off the turbines, causing the engine to lose mechanical power and burst into flames.
You can tear this up all you want, since I'm just pulling it out of what I know vs a logic thought process, (basically my ass, lol), but I know that if you put enough force on the blades of a compressor, it will blow apart, as in an instant explosive force "Wet Start" of a turbine engine and engine failure would occur. Of course, this would not be applicable for an engine that is descending and the RPM and force in increasing gradually. IF the force doesn't blow the engine apart... the overtemp would cause an engine fire which would be very visible to a video camera, though the pilots would still have power, which would deteriorate over time and eventually fail completely. I saw no fires on the 9/11 tapes until after the aircraft crashed. Forget "structural damage" due to overspeed... what about all the other things that we can damage by flying an aircraft out of its envelope?
How would our "novice" terrorist pilots be able to fly wide body aircraft beyond the limits on Boeing's test pilots without over stressing the aircraft while maneuvering anyway other than besides fluke? I've heard from 767 pilots that it maneuvers like a beached whale... intentionally maneuvering and positioning that aircraft into a 200 foot wide building at 450+ knots takes practice and skill. Just cause "terrorists" practiced flying 767s into buildings on Microsoft Flight Simulator doesn't give them the skillset required to achieve such an accomplishment in real life.
P.S. You can barrel roll a 747... I did it on flight simulator!