Worth shooting down one of these, just for the camera, I'd have thought...

FWIW, I think they're missing a trick. The chopper is moving in something approximating a straight line, so the camera only needs to view a wide but thin line across the path, as with a desktop scanner, but on a larger scale. Still, that might save money, and we wouldn't want the military doing anything on the cheap...

Long footprint imaging isn't the pint here - that's old news, has been done for half a century and more. The problem being addressed here is real-time monitoring, which strip scans won't solve - A strip scan still only looks at one thing at a time, albeit over a long period of time and distance. What this is doing is continuous monitoring of multiple discrete locations simultaneously.