Whatever terrorist network was responsible for the 911 attacks would face the same problems. If any of them could shorten the odds of failure by employing a remote guidance system to steer the jets, they clearly would.
Could the alleged 19 hijackers have thought they were taking part in drills that would have seen the jets they were on landed at military bases to play out an end game? Possibly.
Did the technology exist that would have allowed for the flights control systems to be taken over while they were over these bases? Absolutely.
Could 19 amateurs assume skills that would be the envy of the most experienced of pilots and outwit NORAD and the some of the most advanced defense systems that exist, flying around heavily protected and monitored airspace unopposed for extended periods of times before hitting at least 3/4 of their intended targets? Not a chance.
As always, Occams razor cuts both ways.
Asking directly to 911247:
The main problem would be logical.
If the planes were remotely controlled, there are some options:
1) All passengers and crews do not exist
2) Passengers and part of the crew are real, but the pilots, co-pilots, etc never existed
3) "They" killed the pilots and co-pilots previously and flew the plane remotely
There are additional issues:
- did the planes left the airports as reported? If they did, there would need to be lots of participants in all airports to cover the "pilotless" planes. It would make more sense if the 4 planes left the same airport, around the same time.
- if they didn't left those airports, all flight monitoring structure would need to be tampered with so that it looked like they departed from there.
Other than that, a big part of the discussion is if the plane supports those maneuvers at that speed, or even if it's possible to an experienced pilot to fly like that. If the plane do not support that speed at sea level (what I also don't believe), it doesn't matter if it's remotely or locally controlled.
Which option do you believe (or a variation of one of them) and how to solve the additional issues?