Passing planes and other whoosh sounds

I'm just armchair musing here, and I'm definitely no expert on sound waves, but I wonder if they considered the fact that most airliners have more than one engine. Could the effect also be the superposition of multiple engine sounds?

Those have a fixed spatial distance, too, and the effect would (I suppose) change with the lateral angle to the listener during the fly-by. This theory should be pretty easy to falsify, because then the effect would not occur if the plane's path went exactly overhead.