Where was the sun relative to your view? There is an effect called a
"schlieren visualization" that describes why we see
mirages and the like, sort of like seeing the heat rise off a candle. I once
watched a shock wave dance around on the
nacelle of a DC-10. The sun was the "coherent light source" low on the
horizon. It was pretty strange to see. I have
also read that NASA and DARPA have used high power optics from the ground to
observe airflow around an aircraft at high
altitudes.

Dan D.





I once watched the shockwave on the wing of a 757 in flight for quite a
while. It was visible as a noticeable line of refraction in the air over
the wing and it cast very distinct shadows on the wing. The shadows took
the form of arcs similar to shadows cast on a stream bottom by ripples
in the water. An airline pilot friend said they used to see them on the
wings of 727's when they would get up close to their highest cruise
speed.