On the noise issue, I saw one company recently have the idea of keeping the main drone itself at a relatively high altitude, high enough that you can't hear it,

On the noise issue, I saw one company recently have the idea of keeping the main drone itself at a relatively high altitude, high enough that you can't hear it, and lowering its cargo along with an extra device for stability/maneuverability down below. Called zipline. Of course, still far too small to be able to deliver e.g. a fridge, but can easily handle your typical food or small package deliveries.