The article is correct, their explanation is poor. When you hear a sound with your eyes closed you can normally locate where it’s coming from. As in close your eyes and snap your fingers. Now suppose someone sets off a bomb some distance from you. You see the explosion or lightning flash etc but it takes a while for sound to show up. For stationary objects it doesn’t really matter you can still locate direction just fine.
Aircraft in level flight are also loud enough to be heard at distance sufficient to notice a delay. If the aircraft is flying by you hear sound from exactly one instant, but it like the explosion it was produced in the past. So if you close your eyes and try to locate the aircraft by sound you will point to wherever it was when it produced that sound not where it is right now.
The same is true of every sound you hear, but normally distances are short enough and speed are low enough it just doesn’t matter.
Aircraft in level flight are also loud enough to be heard at distance sufficient to notice a delay. If the aircraft is flying by you hear sound from exactly one instant, but it like the explosion it was produced in the past. So if you close your eyes and try to locate the aircraft by sound you will point to wherever it was when it produced that sound not where it is right now.
The same is true of every sound you hear, but normally distances are short enough and speed are low enough it just doesn’t matter.