On the subject of noise that got a mention in Economist as a possible future nuisance in this brave new world.
I started to ponder the energy cost of general purpose deliveries. Amusingly, Paul Merton on Have I Got News for You was also on similar lines. Bloke from matternet passes judgement on AMZN:
Drone expert: Amazon's hypetastic delivery scheme a pie in the sky ? The Register
Dirigible hybrids, hydrogen come back?
Another question would be the tolerance for some low level of injury and death from something that offers both utility and maybe a lowering elsewhere, e.g. road transport.