Any sufficiently advanced technology is
indistinguishable from magic. Clarke's First Law:
Says they are real T-38s in the air - as opposed to models in a wind tunnel.
Google - Air-to-Air Background Oriented Schlieren - or AirBOS.
https://technology.nasa.gov/patent/TOP2-271
"First, images are obtained of a visually textured background pattern from an appropriate altitude. Next, a series of images are collected of a vehicle in flight below the observer vehicle and over the same spot on the ground that serves as a background pattern. Shock waves are deduced from distortions of the background pattern resulting from the change in refractive index due to density gradients.
The invention requires special software to create the schlieren images."
I would dismiss this as utterly implausible and fake other than that I already know of two quite similar seeming things that are both utterly implausible and real - namely CT scans, and MRI scans.