Drone makers race to quieten delivery drones as noise complaints grow

As delivery drones from companies such as Amazon and Walmart become common in the US, residents are complaining about their noise. A Dallas-area woman says the buzz has kept her out of her garden. Amazon Prime Air is expanding to nearly 500 cities and towns and has launched near Darlington, England. Experts say the rotor whine is especially noticeable, pushing manufacturers to build quieter drones.