Scenes like that have been common around here since as long as I can remember - twice a year, on National Guard training week. They mobilize a lot of personnel and hardware during those weeks.
One of the coolest things I ever saw was pheasant hunting on a game farm up by Little Falls, when we began to hear a low rumble. Then appearing very low over the horizon, just over the treetops, a tight group of four C-13 aircraft came right towards us and flew right over just a few hundred feet off the ground, headed straight in the direction of Fort Ripley. It was awesome; ominous looking; deafening.
When I was a kid, we used to camp as a small semi-private lake a short distance from Fort Ripley. During guard training week we could hear loud explosions from the West; looking there at dusk we could see the sky light up. Never knew for sure if it was loud fireworks low to the ground, or Guards training with explosives.
If I was to guess based on what I see in the video, I would think this nothing more than a routine mobilization of the Pennsylvania National Guard - unless and until someone can offer me reason to believe that it is something else.
I got my tin-foil-hat right here, but I only put it on when I think I need it.