I agree on that it is an illusion. If the planes were at same level of altitude, the Japanese surely would have been hit by th full effect of the DHL-plane's engines, resulting in at least some vibrations and tremors, probably trouble with their own engines that were picking up the jetstream, both causing results which would have been reported by excited (or freigthened

) passengers.
Think the airliner was a good ammount of altitude below the DHL plane.
But a scaring shot it is.