Would it surprise you to learn that it is 100% verifiable that crashed pieces, of an identical American Airlines 757 to the supposed 9/11 Pentagon 757, were purchased on the black market in Miami by federal investigators in 1996?
Scavengers took engine thrust reversers, cockpit avionics, and other components from the crashed 757, using Colombian military and private helicopters to go to and from the crash site. Many of the stolen components reappeared as unapproved aircraft parts on the black market in Greater Miami parts brokers.[26] In response, the airline published a 14-page list stating all of the parts missing from the crashed aircraft. The list included the serial numbers of all of the parts.
https://en.wikipedia.org/wiki/American_Airlines_Flight_965#Aftermath
"Turbine Blades - Dozens in jet engine create thrust through air intake and fuel combustion."
"Cost $1,500 each new. U.S. congressional investigator bought blades at Miami scrap yard for $1.30 apiece."
https://www.newspapers.com/image/599000294/
When an American Airlines plane smashed into a Colombian mountainside last December, outlaw salvagers didn’t even wait for all 159 victims’ bodies to be collected before they moved in.
Using sophisticated tools, they extracted engine thrust reversers, cock-pit avionics and other valuable components from the shattered Boeing 757 and then used helicopters to fly the parts off the steep ridge, U.S. and Colombian sources say.
The parts were offered for sale in Miami, a hub of the thriving black market in recycled, stolen and counterfeit aircraft parts.
“They wanted to sell the whole lot, including the landing gear,” a law enforcement source said, speaking on condition of anonymity.
Parts illegally salvaged from crashes, counterfeit parts and other substandard components regularly find their way into the world’s air fleets, sold at bargain prices, often with falsified documents about their origin or composition.
https://www.spokesman.com/stories/1996/dec/08/risky-business-thriving-black-market-in-bad-parts/
So the simple answer, for those exploring whether it was possible for the scene at the Pentagon to have been staged to look like a 757 crash, is yes. The federal government absolutely had crashed airliner pieces from an identical American Airlines 757 on hand and available for use on 9/11.