FEMA Coffins.
We'll have to start placing those everywhere across the United States to make people think we are preparing for a massive disease outbreak, but then instead round everybody up and put them in FEMA Death Camps to "protect them from the flying saucers" we have created through the use of hologram imaging. Then once they arrive at the camps for "protection", we tell them that the burning smell are not bodies but rather the natural smell of aliens and that those large furnaces have ice cream parlours inside for their convenience.
It would be one big massive PsyOp/extermination plan.