The military has admitted that its secure airspace is being invaded at will by solid craft detected by multiple sensors.
Not only can we not stop it, we don't know what it is or who is behind it.
But we do know it has "flight" capabilities (if you can call it flight) which are beyond anything in our inventory.
If these things were armed, our entire military would be of no value against them.
Our military is more interested in fighting man-made global warming than fighting flying craft that invade our secure airspace.