Within a July 18, 2008 Freedom of Information Act response from the National Transportation Safety Board, the NTSB indicates that it possesses no records indicating how wreckage recovered from the 4 aircraft used during the terrorist attacks of September 11, 2001 was positively identified as belonging to the 4 planes reportedly hijacked that day or even if such wreckage was positively identified at all.

Within a similar March 18, 2008 FOIA response from the Federal Bureau of Investigation, the FBI states the following:

"The identity of the three hijacked aircraft has never been in question by the FBI, NTSB or FAA"

http://www.infowars.com/?p=886&cp=1

However, NTSB factual reports pertaining to the Flight Data Recorders allegedly belonging to American Airlines flight 77 (N644AA) and United Airlines flight 93 (N591UA), do not cite a "Flight Data Recorder Group", that would normally consist of Federal Aviation Administration and airline officials, in possession of records pertaining to a given aircraft and unique serial numbers pertaining to each FDR. The absence of published FDR part and serial numbers within each NTSB FDR report suggests that the NTSB were not provided access to such records that would allow them to confirm the identities of the FDRs studied by them.

Many FDRs possess unique memory configurations that are identified by serial numbers contained within a given aircraft's records. Such serial numbers are required to facilitate FDR data readouts. Presumably, if the recovered AA 77 and UA 93 FDR's did not possess the memory configurations indicated within FAA and airline aircraft records, a mismatch could become apparent to NTSB investigators.

http://www.911blogger.com/node/16089

The FDRs in question were apparently recovered by NTSB personnel.

Carol Carmody, Vice-Chairman, National Transportation Safety Board, referring to the NTSB:

"I ... assured FBI Director Mueller that we would assist in any way we could ... he called and said, "Could you send us some people to help find the black boxes and help identify aircraft parts."

http://www.ntsb.gov/speeches/carmody/cc020227.htm

Marion Blakey, Chairman, National Transportation Safety Board, referring to the NTSB:

"Over 60 Safety Board employees worked around the clock in Virginia, Pennsylvania, New York, and at our headquarters in Washington, D. C., assisting with aircraft parts identification"

http://www.ntsb.gov/Speeches/blakey/mcb020625.htm

The text of the July 11, 2008 NTSB FOIA request:

"I respectfully request copies of records revealing the process by which wreckage recovered from the aircraft used during the terrorist attacks of September 11, 2001, was positively identified as belonging to: American Airlines flight 11 (N334AA), United Airlines flight 175 (N612UA), American Airlines flight 77 (N644AA) and United Airlines flight 93 (N591UA).

The afore mentioned aircraft are identified within numerous public NTSB records. Positive wreckage identification was presumably obtained through the use of unique serial number identifying information contained by the said aircraft's wreckage. Within U.S. Code of Federal Regulations (CFR), Title 14, Part 45, it is indicated that all U.S. commercial civil aircraft are required to contain numerous components bearing unique serial number data "secured in such a manner that it will not likely be ... lost or destroyed in an accident"."