It's about altitude and mass. A very small drone (call it 500g AUW) can deliver a pill bottle at maybe 30 meters altitude without you hearing them. Delivering

It's about altitude and mass. A very small drone (call it 500g AUW) can deliver a pill bottle at maybe 30 meters altitude without you hearing them. Delivering a can of soda (5kg AUW), we're talking a bigger, heavier drone and maybe a hundred meters. Delivering a bag of dogfood (50kg AUW), you need to keep the rotors maybe 300m in the air. If you want to keep this quiet in closely space residences you'll need to dangle the package on a wire down from a hover, like a Mars Rover skycrane. In trench warfare, you don't need the wire, you can just drop munitions from altitude, limited only by accuracy. Every domestic drone program is operating under imposed limits on altitude and airspace. A suburban neighborhood has a significant tolerance for noise; We operate leafblowers, lawnmowers, cars and trucks. But only intermittently. If it's right next door to a droneport, the skycrane strategy doesn't help and your house is going to hear that nonstop. It seems like if they were operating from a better more remote facility, and the noise was only intermittent, people in the article might have tolerated even these ~100 pound class drones which have no skycrane and employ full descent almost to the ground (where they unceremoniously drop their contents the last ten feet). Example landing: https://www.youtube.com/watch?v=QcxfcMmdRCM https://www.youtube.com/watch?v=QcxfcMmdRCM