Only one item can be delivered at a time. It can’t weigh more than 5 pounds. It can’t be too big. It can’t be something breakable, since the drone drops it from 12 feet. The drones can’t fly when it is too hot or too windy or too rainy.
You need to be home to put out the landing target and to make sure that a porch pirate doesn’t make off with your item or that it doesn’t roll into the street (which happened once to Lord and Silverman). But your car can’t be in the driveway. Letting the drone land in the backyard would avoid some of these problems, but not if there are trees.
Amazon has also warned customers that drone delivery is unavailable during periods of high demand for drone delivery.
I’m sure being too loud is an issue, but it’s not the issue. That’s like saying the reason we don’t all have castles is due to municipal zoning laws. Sure, that would make having a castle harder, but it’s not the issue.
Yes, “flying cars” are loud, but that’s a minor issue compared to the other ones. They’re expensive to operate. They’re dangerous both to their passengers and to people on the ground. They’re extremely expensive. The infrastructure isn’t available. They’d require training to operate, etc.
If you could wave a magic wand and make all those other problems disappear, the noise issue would still be a blocker. But, the noise issue isn’t the biggest current blocker.