Not doable other than possibly in a DARPA prototype lab and not sensible anyway.
He is talking about dynamically steering the reflected beam, not just tuning the reflectivity. You would need mirrors on piezo controls, at least a pair, that would pivot on on 3D axis to steer the beam back to where it come from.
No one would ever do it that way. In a military application, you would just fire your own laser beam (or other weapon) back at the incoming fire. Why bother with reflecting the beam?
The legalities of a civilian airliner firing back at civilians on the ground is a whole ‘nother matter.
Steve I wasn't suggesting returning the energy to the source, though that is commonly done with field artillery, and has been done for fifty years or so, with artillery tracking radar. Firing artillery shells at an aggressor, shells in the air while the incoming is still flying is common. I've done it, though they wouldn't allow us live rounds, which disappointed my team. But steering cockpit windows would be a challenge. It does remind me of some enormous phased array radar antenna that track missiles without physically moving the transmitter elements, but I'm not proposing that for a defensive coating.
But I surmise that piezo-controlled thin film could diffract or reflect enough of the energy to protect the humans from incoming lasers. And yes. Darpa would be one place to do it. Having worked on Darpa projects at a government lab, if you want it done efficiently, use the private sector. Sounds like you may know about that?
We did use piezo-controlled mirrors to eliminate most atmospheric diffraction from earth-based optics, usually mirrors, for astronomical and other applications, as you can probably imagine. There are some very big telescope in Hawaii that use the technique to great advantage, almost eliminating the advantage of space-based telescopes, where diffraction from atmospheric effects causes stars to ‘shimmer’.
With the proliferation of laser devices it wouldn't surprised me if some functionally equivalent technology were to become necessary, perhaps along with closing passenger windows for takeoff and landing.