Zipline raised $1.5 billion at a $21.5 billion post-money valuation, more than doubling its valuation from earlier this year, and agreed to add 300 Walmart drone delivery sites nationwide. Paradigm, WCM Investment Management and Layer Global led the round, joined by several other investors including Walmart partner Uber. Zipline said it will use the proceeds to expand U.S. manufacturing facilities and hiring. Chief Executive Keller Cliffton, who co-founded the company in 2014, said the higher valuation reflects broader acceptance of autonomous delivery among investors and commercial partners. Walmart’s drone program has completed more than 2 million deliveries, while Zipline said its drones made more than 1 million deliveries in the Dallas-Fort Worth metroplex this year. The companies currently operate 21 sites in Texas and Arkansas, with deliveries available in as fast as 30 minutes for tens of thousands of eligible items.