The Planes! The Planes!
The 1960's Operation Northwoods is a reasonable start, where hijackings would be faked, the "hijacked" planes would be landed and substituted for remote control drones that would then be shot down. The passengers on the fake hijacked planes would be given new identities.
We know that Al Qaeda had some idea since 1995 to hijack multiple airplanes and blow them up over the ocean (Operation Bojinka).
Clearly a tactic as old as airplanes is suicide piloting the plane into some target to inflict damage. This was used effectively by the Japanese in World War II.
We also know the military/NORAD had been practicing hijacking drills, and NORAD as well as the Pentagon and the NRO had been running plane into building drills. So they were thinking about this sort of attack. Clearly these drills and exercises are what the 9/11 planners had in mind for the attacks.
The question is, if you were going to try to engineer something like the 9/11 hijacking attacks (putting aside why you would do it), HOW would you do it?
First of all, you'd have to work in the military, or be affiliated with the military, where you would have access to drone aircraft that could be piloted remotely into targets. The Air Force certainly has these-- they had used them in previous exercises. Moreover, these aircraft were often old commercial jets. While conceivably you could install remote control piloting equipment into standard commercial aircraft, this presents problems. For instance, if there are real hijackers, how do you coordinate the hijacking with the take-over by the hijackers and how do you make sure the pilots don't warn air traffic control of a hijacking? If there are no real hijackers, how do you prevent the pilots from alerting air traffic control of a problem with their plane? Plane-swapping seems to be a better solution-- where you have fake-hijacked commercial planes that are switched with remote-control drones.
How would you set-up such a plane swap? Have the Air Force or NORAD run a "hijacking exercise"-- ostensibly an exercise designed to test the air defense response to terrorist hijackings. This would be the perfect way to plan the attacks without anyone except who was in on the plan to know about it. Have the passengers on the plane think they were part of a "terror drill" and have them make calls to outside people to enhance the realism of the exercise and provide a nice confirmation that nasty terrorists indeed had taken over commercial aircraft. Part of the exercise would involve having the drones programmed to fly into targets, such as the WTC and Pentagon, and the job of air force interceptors is to shoot down these hijacked craft before the drones strike the targets. However, to make sure the interceptors DON'T do their job, extra blips could be inserted into the radar to mimic extra hijacked planes, thus making it impossible for a pilot or commander to decide which planes to go after. These extra blips would also confuse the air traffic controllers and facilitate the plane swap! Indeed, flights 11, 175 and 77 may all have been switched while the exercise was going on-- supposedly one the WTC was hit, the exercise was caled off and the extra blips removed. Supposedly.
What could go wrong?
Well, the main problem would be if a drone aircraft crashed into a target, such as the WTC or Pentagon, and people found out it wasn't the right commercial aircraft. In particular, a head-on crash into a building is unlikely to damage the tail of the plane. Yet the tail of the plane has important identifying information: the tail number, and the tail is also where the black boxes (the flight data recorder and the ccokpit voice recorder) are kept-- precisely because this part of the plane is usually the least damaged in a crash.
What if someone photographed or found the tail of a plane that crashed into a building, and they could see it was clearly the wrong plane? This would be real trouble.
This is why I believe the drone planes HAD to carry extra explosive devices to disintegrate the tail of the plane upon contact.
I think this is why no tails were found in the Pentagon or Shanksville crashes-- even though the crash was head-on and the plane blew up on contact. In a normal crash, the tail should have separated from the plane and would have been found intact away from the crash. But in fact, an odd thing about both the Pentagon and Shanksville crashes is the lack of an intact tail. The tail exploding may be why the video of the Pentagon crash has been edited so severely-- they don't want you to see the tail blowing up. Perhaps the plane was indeed a 757-- but a 757 drone that blew up abnormally upon contact.
I think this point about the 9/11 planes' tails is critical. There is also the issue of whether the planes had special reinforced wings, as I discussed earlier. Both of these are key apsects of the 9/11 physical evidence.