Business
'An annoying buzz': The search for stealthier drones
As drone deliveries become more commonplace, their makers are looking for ways to make them quieter.
BBC Business•
Nature lover Ashley Schmidt no longer spends much time in her garden, in the Dallas suburb of North Garland.
She's also given up on cycling to the local parks where she previously enjoyed taking close-up photos of the bugs, lizards and toads.
It's all because she can't stand the sound of the delivery drones that fly overhead, depositing her neighbours' online orders.
The London-based business has designed a propulsion system it claims can reduce drone noise by at least two thirds.