This article leaves out air traffic control, which is a major issue. In the US, ATC is a very manual process, and planes get slotted into routes that are more

This article leaves out air traffic control, which is a major issue. In the US, ATC is a very manual process, and planes get slotted into routes that are more a factor of what the ATC personnel can deal with than anything else. In most cases, aircraft get lined up in the sky in lanes. If your plane is nice and new and can move efficiently at a higher speed, it doesn't matter because it will get stuck behind an old crappy plane that cannot.