Amazon's desire to deliver items quicker is driving its investment in automation.
By the end of this year it will begin delivering packages weighing up to two kgs in less than an hour from warehouses in Lockeford, California and College Station, Texas.
The company aims to deliver 500 million packages by drone by the end of the decade, including in major US cities such as Boston, Atlanta and Seattle.
Around 75 percent of Amazon's five billion annual orders is handled at some point by a robot, according to Joe Quinlivan, vice president of Amazon Robotics.
For decades the conventional wisdom was that increased automation destroys workforces.
Studies now suggest that moving towards robots in e-commerce will not lead to massive job losses in the short to medium term due to the huge growth in demand.
However, a 2019 study by the University of California's Labor Center at Berkeley warned that while some technologies can alleviate arduous warehouse tasks, they could also contribute to increasing the "workload and pace of work."
The researchers added that technological advancements might also contribute towards "new methods of monitoring workers," and cited the Amazon's MissionRacer video game "that pits workers against one another to assemble customer orders fastest."
Amazon says its innovation has generated more than a million jobs and 700 new job categories, mainly in highly specialized engineering, but also as technicians and operators.
"I really think what we're going to do in the next five years is going to dwarf anything we've done in the last ten years," says Quinlivan.
