Not quite an answer to your question, but in the 60s and 70s hijackings were quite common (86 hijackings in 1969) and weren’t seen in the way they are now. The common understanding was that the hijackers wanted to re-route the plane somewhere else, and that everyone would end up alive but inconvenienced.

It’s also one reason why only the passengers in United 93 fought back; the idea of a plane as a missile wasn’t widely understood or considered until the planes hit the twin towers. Fighter jets were not even under consideration to be mobilized until United 93.

> It’s also one reason why only the passengers in United 93 fought back; the idea of a plane as a missile wasn’t widely understood or considered until the planes hit the twin towers. Fighter jets were not even under consideration to be mobilized until United 93.

Sadly this is mostly a myth. It is a little known fact that there were five separate U.S. military war games being run simultaneously with 9/11 and three of them involved airliner hijacking scenarios, including flying airplanes into buildings. Worse, these war games involved simulated inputs into NORAD and FAA radar systems, resulting in mass confusion. There is an excellent documentary that covers these war games, including actual NORAD, FAA and EADS audio [0].

[0]: https://www.corbettreport.com/911wargames/

I thought I remembered the plot to the 1996 film “executive decision” as being a debate whether to shoot the passenger jet out of the sky because the plane was going to be used as a missile, but i just read the plot again and they were going to detonate a nerve agent bomb on board the plane while over a us city, so, similar but not quite a prediction of the predicament.

I just started watching the historical footage from CNN; it's interesting to hear the commentary in between when the first and second planes hit the tower.

"Was the plane having any difficulty flying?" "Yes, it seemed to be rocking back and forth" "Was this a navigational error?"

An announcement in the South Tower immediately after the crash instructed people to stay in their offices.

Even after the second tower was hit, the immediate reaction was that it was a second explosion in the North Tower caused by the fuselage of the plane.

4 minutes after the second plane hit, when it was clear that two planes were involved: "was it possible a navigational error directed two planes into the World Trade Center?"

It's incredible to think just how much our attitude and perspectives changed after realizing what exactly had happened.

It must be so difficult to do command and control in a situation like that. So many different agencies with diffetent expertise and patchy data.

Maybe large buildings should have cameras pointed at them with IR modes. Feed it to a national control centre that has experts on staff and links to other agencies. And make those kind of judgements thats will seem obvious in hindsight.

That depends on the channel though. On one labeled "NEWSW" they said "I think we have a terrorist act of proportions that we cannot begin to imagine at this juncture. " immediately after second hit.

(Spoilers)

The end of Tom Clancy's 1994 book "Debt of Honor" featured a 747 being crashed into the Capital, which is about as close as fiction gets.

A bit closer is the X-Files spinoff The Lone Gunmen, where a March 2001 episode featured a plot to crash an airliner into the world trade center and blame it on terrorists to justify a new war.

Obviously 9/11 wasn't some government conspiracy to purposely spark new wars, but the other details are eerily similar.

A plot one of the stages of which included potentially crashing an airplane into WTC[0], among other targets, was uncovered (mostly, it appears, by accident) and thwarted in the mid-nineties. The Lone Gunmen plot coincidence is less curious considering that plot could have served as an inspiration, although the means of hijacking were very different in the series.

The sad thing is that uncovering that plot didn’t help prevent the actual attack based on it a few years later…

[0] https://en.wikipedia.org/wiki/Bojinka_plot#Phase_III:_CIA_pl...

Wow 86 hijackings and nobody in intelligence could ever conceive of how that could go horribly wrong

Most people survived them though so there wasn't a huge reason to do anything particularly drastic, using planes as a suicide missile was basically entirely new. Even on the day of there was speculation about why the planes 'messed up' and flew into the WTC buildings which shows just how unusual it was. Most hijackings were essentially mass kidnappings for ransom to get money, release prisoners or get promises of policy changes and ended with a negotiation or storming the plane.

This is covered in the 9/11 commission report. Quoted below:

The protocols did not contemplate an intercept. They assumed the fighter escort would be discreet, “vectored to a position five miles directly behind the hijacked aircraft,” where it could perform its mission to monitor the flight path of the aircraft.

In sum, the protocols in place on 9/11 for the FAA and NORAD to respond to a hijacking presumed that:

(1) the hijacked aircraft would be readily identifiable and would not attempt to disappear;

(2) there would be time to address the problem through the appropriate FAA and NORAD chains of command; and

(3) the hijacking would take the traditional form, not a suicide hijacking designed to convert the aircraft into a guided missile.

On the morning of 9/11, the existing protocol was unsuited in every respect for what was about to happen. What ensued was the hurried attempt to create an improvised defense by officials who had never encountered or trained against the situation they faced.

In 1999 there was a professional golfer named Payne Stewart who died on a Learjet flight along with five others after it depressurized mid-flight. The plane continued flying on auto pilot and the FAA scrambled three separate fighter jet interceptions, involving five F-16s, the first one making visual contact with the Learjet approximately 20-30 minutes after the Learjet pilots became unresponsive. There was speculation at the time that the FAA was prepared to shoot the flight down if it was at risk of crashing in a populated area. The Pentagon later denied this, however, the Canadian government said this was their policy should the flight enter their airspace. [0]

[0]: https://en.wikipedia.org/wiki/1999_South_Dakota_Learjet_cras...

Yeah, I don’t think 3 can be overstated.

Prior to 911, hijacked planes were not an unknown thing. I don’t know numbers, but remember periodic events in the news of x plane that was hijacked landing at y airport with local officials needing to meet hijacker demands for it to return to its flight.

Was weird when it happened, but we also didn’t have the hour of processing through security we do now.

You can listen to real-time audio of FAA and NORAD track planes and scramble fighters [0]. This is not an easy task considering nobody knows what is happening and literally every plane in the country is being redirected and landed simultaneously.

[0] skip to about 20min https://youtu.be/DYBhgEm3j7A

Few people would want to make a call to shoot down two full passenger jets over a city. With hindsight it would have been the right option, but at the time it's unlikely it would have happened even if there had been fighters with missiles available.

Hijackings also weren't usually suicide missions before then either so it would have been a big leap to decide to shoot them down when you'd normally expect demands and a chance to take it out on the ground rather than just killing everyone on board.

Al-Qaeda actually gamed out this aspect of the American response and concluded (apparently correctly) that the US was ill-prepared for a multi-hijacking scenario. This wasn't rocket science... They basically looked at all available information on threat modeling the US had done, and noticed that we had constrained ourselves to a single hijacking event. They correctly surmised that intelligence infrastructure (including NORAD) would be off of their playbook if they hijacked multiple planes at once.

This led to disruption of the response. When flight 77 (Pentagon plane) was reported as having dropped off of the transponder radios, by the time NORAD was notified the information had become garbled in a game of telephone and they thought they were receiving reports on flight 11, which is one of the two that struck the Trade Center towers. They scrambled jets to New Jersey instead of onto any predicted flight path for flight 77.

We did mobilize fighter jets (albeit without missiles, so essentially if the pilots intercepted it’d likely be a suicide mission). Also after 9/11 people straying in to no fly zones over DC would be escorted out by fighters.

IIRC the fighters that were mobilized planned to ram since they took off without time to load missiles onboard, but all of our fighter keys have ejection seats. I assume the plan was to eject.

To ensure the fighters crippled the passenger plane, at least one of the scrambled National Guard pilots ruled out ejecting.

The other hoped to eject before impact.

https://www.nbcnews.com/id/wbna44459345