About 50 individual customers placed orders with Swiss online shopping platform Siroop, choosing "airmail deals" from selected items from retailer Black & Blaze Coffee Roasting Co. for same-day delivery. The drones then flew to four fixed points in the city, covering a distance as far as 17 kilometers (11 miles) to land on the roofs of specially adapted Mercedes-Benz Vito vans. The parcel is carried by road for the final stretch, before the drones return.

"Our expectations were all met -- our main goals were about the technical feasibility and execution," Corinna Elosge, who coordinates the last mile logistics vans and drones project for Mercedes' parent Daimler AG, said in an interview. "We're really, really satisfied because we had a perfect safety score."

The miniature helicopters, developed with U.S. company Matternet, delivered parcels for a total of 11 days as part of a three-week test. Daimler last year said it was looking at drones as part of a 500-million-euro ($597 million) effort to speed delivery times for online orders, amid the boom in electronic commerce. Amazon.com Inc. in December made its first-ever drone delivery, while convenience store chain 7-Eleven last year flew a parcel of chicken sandwiches and doughnuts to a private residence in Reno, Nevada.