WELL! T he PHd is entitled to his opinion, the still photo sure makes it clearer.
As far as wake turbulence blowing dust from a 400 knot airplane @ 100 feet---only in hollywood 
And the noise level---take a look at the nacelles, the original low bypass engines have been replaced and I'll wager a quart of Southern Comfort that high-bypass engines set to a low cruise setting (as in a diving pass) would be a mere whisper (comparatively) My degree in Bovine Scatology and 50 years of watching airplanes gives my opinion just as much weight as the professors 
Actually you should see some dust etc, or even wind from the wake turbulence. Have you seen the dryden test center photos from nasa on their studies on wake turbulence? They arent even using a heavy and its really impressive video/pictures of how the air moves etc. You should see some dust/wind in the trees from this and there isnt any.
Ok folks, lets take a deep breath and think---This KC 135 is traveling every bit of 400 knots, without dragging out my E6B that's in the neighborhood of 625 feet per second (estimated)---that's 2 Yankee football fields in UNDER 1 second.
The maximum vortice produced by an aircraft is at lift off because the wing's angle of attack at rotation is very high thus producing a large quantity of slow air moving lengthwise and spilling off the wingtip to produce the a large vortice typically seen in dust tracks (pretty much the same thing on approach and landing but the airplane is much heavier at takeoff and we all know that heavy, slow airplanes produce the largest strongest vortice) ---think about that---
As the aircraft increases speed, the flaps and slats are retracted and the AOA decreases and less vortice is produced so that at high cruise speeds the vortice is much smaller and weaker.
Now look at the NASA footage posted by undatc, a dirty C-5 in landing configuration passes over a 100 foot tall smoke tower at about 200 knots OR SLOWER (300 feet per second) at between 4 and 500 feet, The smoke coming from the top of the tower (roughly 300 feet below the A/C) is not affected in a major way until about 3 to 5 seconds (9- 1500 feet) AFTER A/C passage and don't forget that a slow C-5 has an extremely strong vortice!
NOW, take another look at the KC135 low pass--the camera is aimed at the airplane and cannot capture any dust blowing hundreds of feet behind it--remember the vortice disturbance is small because of the speed and low AOA and is also farther behind the airplane because of the speed----You ARE NOT going to see any wake distubance from those angles.
In hollywood, when Clint Eastwood flies a Soviet fighter over the snow at Mach 2 you will see snow flying directly under the airplane as it goes by BUT, that's hollywood kids--it doesn't work that way in real life.
After more views and Franks stop action picture AND the aforementioned facts I am now inclined more than ever that this is a balls out low pass by some folks having fun in a dangerous way at taxpayers expense
If anyone can PROVE me wrong, I'll send you that bottle of Southern Comfort, till then, I'm listening.
