He described the exact plot of the pilot episode of The Lone Gunman in that YouTube link., The Lone Gunman was like the Mr. Robot of March, 2001.
The popular cultural notion that airliners could be used to crash into the World Trade Center had been floating around for decades prior to The Lone Gunman. I had first come across it in 1989 or so, but I suspect it goes all the way back to 1973. It wasn't a unique or new idea.
Assassinating the president is as old as Rome, but if there was a TV show from March, 1963 where the military-industrial complex, mad at the president for not escalating Vietnam, decided to kill him by hiding a gunman in a building along his route in Dallas, We’d still be talking about it now.