The electronics to control and guide either a “quad-copter/hexa-copter” or an old fashioned model airplane are readily available and could be adapted to very large model aircraft or to an old Cessna 150/152 two seat airplane.
The Cessna 152 can legally carry about 500#, less 36# for an hour’s worth of fuel. It would fly at about 100-110 mph. A used 152 in flyable shape could be bought for $15K or less.
The “bad guys” have already thought of this, so I’m not “giving away the store.”
“The best defense is a good offense.”
...Imagine a payload of scores of smaller quads as per my post 22, launched like paratroops with a scatter program.
Micro mass has a quality of it’s own.