We're told that the Pentagon fire consumed most of the aluminum wreckage, and yet it was still possible to identify all but one of the passengers. This simply isn't possible, and tells us there's something wrong with the official account.
It’s difficult to destroy DNA. Essentially you need a complete cremation, turn even bones to ash, and that doesn’t happen easily. Use Google to search for references to "Crematorium" and you'll find items like this.
New crematoriums, constructed on or after August 30, 1989, must have at least a 1.0 second interval at which the temperature reaches 1800°F. And, the operating temperature must never go below 1600° F
In a cremation, the casket or container is placed in a chamber, where the temperature is raised to approximately 1000° C (1832° F). After approximately 90 minutes, all organic matter is consumed by heat or evaporation.
So it’s recommended to take 90 minutes at a constant 1800 degrees F to cremate a body. Fire persisted for many hours at the Pentagon, but with that temperature all around the passengers bodies? Or did the fire move on elsewhere?.
We can perhaps get some clues from sites that discuss the WTC fires (see http://www.plaguepuppy.net/public_html/Confronting%20the%20Evidence/annotations_2.htm). Here they talk about temperatures typically reaching 1432° F (800° C), with occasional higher values for very brief periods of time. Given that these fires weren’t lasting for anything like 90 minutes in the same place, though, it seems unlikely that you’d see complete cremation. This would still have made identification difficult, but there’s no reason to believe DNA testing wouldn’t be possible. Read this account of a tunnel fire in Austria, November 2000:
Austrian officials said most of the 66 bodies so far recovered were so badly burned, the remains would require DNA testing and that it would take at least three days to get the results of each test...
The intensity of the fire left the bodies badly charred and even tattoos and scars could no longer be seen, chief forensic pathologist Edith Tutsch-Bauer said...
The tunnel scene was a melted morass filled with bodies. Major Franz Lang, the officer in charge of the rescue operations, said the rescue teams were having "to cut out, to dissect, each victim."
Bodies and remains were stuck among parts of the melted train, ski clothes, boots and other equipment. The floor of the train melted, in temperatures estimated at over 1,000 degrees centigrade.
1,000 degrees centigrade is enough to cremate bodies, but there’s no suggestion here that that happened, and it appears DNA identification was at least believed to be possible.
DNA appears to have survived, then, in temperatures high enough to melt the floor of the train, and if the same fire had occurred in a plane then the damage would have been even worse: aluminium has a melting point of 1220° F (660° C). Here’s a couple of examples of how planes can be gutted by fire:
And these were from an Air France flight that caught fire after overshooting the runway (there were no fatalities). In this case the wings remain, as there was no impact, but what might have been left if the plane had smashed into a particularly solid building at around 500 mph?
This page explains some of the forensic radiology issues in identifying the Pentagon bodies:
And the Disaster Mortuary Operational Response Teams were involved in the process: