When Did the Military Learn About the Four Hijacked Flights?
A synchronized look at FAA recognition, military notification, and the changing public chronology of September 11.
On September 11, 2001, there was no single moment when “the government” learned that four aircraft had been hijacked.
Controllers, airline personnel, FAA facilities, military air defenders and national command authorities learned different things at different times. Information moved through separate channels, sometimes slowly and sometimes incorrectly.
The distinction matters.
For an air-defense response, the critical question is not simply when someone in the aviation system realized that something was wrong. It is when useful information reached the people who could identify, locate and respond to the aircraft.
The 9/11 Commission eventually reconstructed that sequence using FAA and military recordings, radar data, logs and interviews. Its resulting chronology differed materially from several earlier public accounts.
The Four Flights
American Airlines Flight 11
Boston Center became aware that American 11 had been hijacked before the military was notified.
At 8:37:52 a.m., Boston Center reached the Northeast Air Defense Sector, or NEADS. According to the Commission, this was the military’s first notification “at any level” that American 11 had been hijacked. NEADS then ordered two alert F-15s at Otis Air Force Base to battle stations.
American 11 struck the North Tower at 8:46:40. The Otis fighters were ordered to scramble shortly before the impact and became airborne afterward.
What the record shows: the FAA recognized the hijacking before NEADS was notified. Once NEADS received the call, the available response window was measured in minutes.
United Airlines Flight 175
United 175 presented a different problem.
New York Center suspected that the aircraft had been hijacked, but the first indication NEADS received that there was a second hijacked aircraft came at approximately 9:03 a.m.—about the time United 175 struck the South Tower at 9:03:11.
The Commission’s final chronology placed the formal notification that United 175 had been the second aircraft to hit the World Trade Center later, at approximately 9:15.
What the record shows: military air defenders did not receive actionable advance warning of United 175 in time to intercept it.
American Airlines Flight 77
The chronology of American 77 became one of the most important disputes in the public account of the air-defense response.
Flight 77 turned away from its planned route at about 8:54 and its transponder was turned off at 8:56. American Airlines headquarters believed by approximately 9:05 that the flight had been hijacked, while FAA facilities were searching for the missing aircraft.
At 9:24, NEADS scrambled fighters from Langley Air Force Base.
For years, that scramble was publicly described as a response to information about American 77—or, in some accounts, United 93.
The recordings-based reconstruction produced a different explanation.
The 9:24 information reaching NEADS concerned a mistaken report that American 11 was still airborne and heading toward Washington. The Langley fighters were scrambled in response to that phantom aircraft, not a confirmed report that American 77 had been hijacked.
At approximately 9:34, the FAA advised NEADS that American 77 was missing. Minutes later, NEADS was told that an unidentified aircraft was approaching Washington. American 77 struck the Pentagon at 9:37:46.
United Airlines Flight 93
United 93 was still operating normally at 9:16, despite later testimony that NORAD had received a hijacking notification at that time.
The hijackers seized the aircraft beginning at approximately 9:28. By 9:34, the FAA Command Center had advised FAA headquarters that the flight was hijacked. United itself concluded by approximately 9:36 that the aircraft had been hijacked.
The aircraft crashed near Shanksville, Pennsylvania at 10:03:11, according to the Commission’s reconstruction from radar, flight-recorder, cockpit-voice-recorder, satellite and air-traffic-control evidence.
NEADS first received a call identifying United 93 as hijacked at 10:07.
By then, the aircraft had already crashed.
What the record shows: FAA elements knew United 93 was hijacked before the crash, but NEADS did not receive that hijacking notification until afterward.
The Morning in One View
| Flight | FAA / Airline Recognition | Military Notification | Outcome |
|---|---|---|---|
| American 11 | Boston Center aware by about 8:25 | 8:37:52 — Boston Center reaches NEADS | 8:46:40 — North Tower |
| United 175 | New York Center suspects hijacking before impact | About 9:03 — NEADS first learns of second hijacked aircraft | 9:03:11 — South Tower |
| American 77 | American Airlines aware by about 9:05; FAA search underway | 9:34 — NEADS told Flight 77 is missing; no earlier confirmed hijacking notice | 9:37:46 — Pentagon |
| United 93 | FAA Command Center tells headquarters by 9:34 that Flight 93 is hijacked | 10:07 — Cleveland Center military liaison tells NEADS | 10:03:11 — Pennsylvania |
These times track the recordings-based chronology later adopted by the 9/11 Commission.
For each hijacked aircraft, military response depended on information moving through a civilian system that did not provide air defenders a complete picture in time.
That does not mean the FAA knew nothing.
It means that different parts of the system possessed different pieces of information, and that recognizing a hijacking somewhere inside the civilian aviation system was not the same thing as getting timely, actionable information to NEADS.
That distinction becomes especially important when comparing the later recordings-based chronology with the public timeline initially presented by NORAD officials.
The Public Timeline Changed
At a May 2003 hearing of the 9/11 Commission, NORAD officials gave a chronology that appeared to provide substantially more advance warning of American 77 and United 93.
Colonel Alan Scott and Major General Larry Arnold described a 9:24 notification involving American 77, and Arnold testified that he believed that was the first notification NORAD received about the aircraft as a possible hijacking. The same presentation placed a possible United 93 hijacking notification at 9:16.
A year later, the Commission publicly rejected both claims.
American 77
Earlier account:
NEADS received notification of the hijacking of American 77 at approximately 9:24, leading to the Langley scramble.
Recordings-based account:
The 9:24 information concerned the mistaken report that American 11 was still airborne and heading toward Washington. The Langley scramble was prompted by that phantom Flight 11 report.
United 93
Earlier account:
NEADS received notice of a possible United 93 hijacking at approximately 9:16.
Recordings-based account:
United 93 had not yet been hijacked at 9:16. NEADS first received a call identifying it as hijacked at 10:07, after the aircraft had crashed.
Thursday, June 17, 2004 Hearing
The Commission stated explicitly that these earlier accounts created the appearance that the military had more time to respond than the later evidence supported. It also concluded that the inaccurate chronology overstated the FAA’s ability to supply timely and useful information to the military that morning.
The response failed—and the first public account gave the military more warning time than the recordings later supported.
That is a documented change in the public chronology.
It does not, by itself, establish why the inaccurate notification times were originally presented, whether individual witnesses knowingly supplied false information, or why the erroneous chronology persisted for years.
Those are separate evidentiary questions.
What Changed Between 2003 and 2004?
The key difference was access to a larger body of underlying records.
By the Commission’s June 2004 hearing, staff had reconstructed the morning using taped FAA and NEADS conversations, event logs, chat logs, radar data and other records. The Commission stated that the mistaken American 11 report appeared not only on NEADS recordings but across FAA and NORAD records.
General Arnold, questioned about his earlier testimony, said that when he appeared before the Commission in 2003 he had not had the relevant notification times available and had been trying to remember what caused the Langley scramble. He said he initially thought it had involved United 93.
That explanation belongs in the record.
So does the contradiction.
The appropriate evidentiary conclusion is not that one explanation must automatically be accepted or rejected. It is that the 2003 public chronology and the recordings-based 2004 chronology are materially different, and the later reconstruction reduced the amount of warning time attributed to the military.
Why the Difference Matters
If NEADS had actually been told at 9:24 that American 77 had been hijacked and was approaching Washington, then the military would appear to have had roughly fourteen minutes before the Pentagon was struck.
The later reconstruction says it did not.
According to the Commission, NEADS had at most one or two minutes after receiving warning of an unidentified aircraft approaching Washington, and the Langley fighters were not positioned to intercept it.
Likewise, a 9:16 United 93 notification would suggest nearly three-quarters of an hour of military awareness before the aircraft crashed.
The recordings-based account says that notification never occurred.
NEADS learned of the hijacking after the crash.
This is why notification time is not a minor technical detail.
It changes the question being asked.
Under the early chronology:
Why did the military fail despite substantial warning?
Under the later chronology:
Why did the civilian and military systems fail to develop and transmit a usable common picture before the attacks were completed?
Those are different failures.
What the Record Establishes
The surviving records support several conclusions.
- American 11: Boston Center notified NEADS at 8:37:52, less than nine minutes before impact.
- United 175: NEADS first learned of the second hijacked aircraft at approximately the time it struck the South Tower.
- American 77: the Langley scramble was initiated because of the mistaken report that American 11 remained airborne, not a confirmed Flight 77 hijacking notification.
- United 93: FAA elements knew the aircraft was hijacked before it crashed, but NEADS received its first hijacking notification at 10:07, after the crash.
- The official chronology changed: key notification claims made publicly in 2003 were rejected by the Commission in 2004 after the underlying recordings and records were examined.
What Remains Unresolved
The chronology tells us what information reached particular parts of the system and when.
It does not fully tell us why the information system performed as it did.
The recordings-based reconstruction does not by itself establish:
- why inaccurate notification times were initially presented publicly;
- why those accounts persisted;
- whether any individual knowingly provided false testimony;
- whether other channels possessed useful information that was not transmitted to NEADS;
- or whether different procedures could realistically have produced successful interceptions in the remaining time.
Those questions require evidence beyond the notification timeline itself.
Primary Record
The most important source for this chronology is the 9/11 Commission’s reconstruction of the flights, FAA communications and military response.
The Commission’s June 17, 2004 hearing is especially important because staff played and summarized the underlying FAA and NEADS recordings and directly compared them with the earlier public testimony.
From the Archive
911Truth.org has published extensive historical analysis of the NORAD tapes and the changing air-defense chronology.
These articles are preserved because they document how researchers understood and contested the record as additional evidence became public. Their interpretations should be distinguished from the narrower conclusions established directly by the recordings.
Kevin Ryan
“Never Forget: The 9/11 Air Defense Failures”
Best fit of the three for this new article because it directly tracks the changing NORAD/Commission chronology and the air-defense response.
David Ray Griffin
“Do the NORAD Tapes Verify The 9/11 Commission Report?” · September 14, 2006
Griffin examines the differences between the earlier NORAD chronology and the later tape-based account. His article contains extensive discussion of American 77 and United 93, while advancing broader conclusions about deception that go beyond what the recordings alone establish.
NORAD Live and Uncut
Staff · August 31, 2007
911Truth.org also preserved reporting on the public release of a much larger collection of NORAD recordings, providing historical context for the source-recovery effort surrounding the air-defense record.
