When 9/11 happened, the drive-bys were marveling at the novelty of the idea of turning airliners into missiles.
But at the time, I remembered the FedEx real-life case and had read Tom Clancy's fictional imaginings (disgruntled JAL 747 Captain Sato and the Capitol in the middle of a SOTU). So, the concept wasn't new to me, LOL!
I remember when I finished reading Debt of Honor. I kinda stopped and thought "did he really just kill off the entire congress?" Then I went back to re-read the last few pages. There was something deeply satisfying about it.
Kinda like when Independence Day was first in theaters. When the White House was blown up, people in the theater cheered.
There was also another older movie, cannot recall it's name, about Air force One being hijacked for the same purpose.
There is only one problem with the concept of airliners being used as a missiles. Their engines compress air. Due to air density close to the ground, when they fly at very low altitude they can not fly faster than 250 knots. The only way to gain high speed at low altitude is to nosedive them from cruising speed at high altitude, but they would probably disintegrate mid-air. So airliners as missiles is is mostly Tom Clancy/F-X territory.