Drone delivery bulls took a hit after news of Amazon's (NASDAQ:AMZN) floundering U.K. drone operations broke on Tuesday, but plenty of smaller players are still working to bring drones to U.S. cities. The latest locale? Phoenix.

South Korea-based Pablo Air announced Wednesday the expansion of its drone delivery business into Phoenix, signing a memorandum of understanding with three local companies to begin testing its established services, as well as its newer innovations. The MOU loops in full-service logistics provider NGL Transportation, whose clients include retail giants Walmart (NYSE:WMT) and Amazon (NASDAQ:AMZN).

"We plan to demonstrate Pablo Air's unique technology in the global market by implementing practical commercialization along with a demonstration of delivery in the United States, for the first time as a Korean drone startup," said Kim Young-Joon, CEO of Pablo Air. "Afterwards, through continuous development, we will resolve difficulties related to long-distance delivery and the accessibility of existing delivery systems in logistics by raising the efficiency of various mobility vehicles, such as self-driving trucks and unmanned ground robots as well as delivery drones."

Another partner, Deliver-EZ, is collaborating with the company to establish an affordable mailbox and an unmanned delivery station, both optimized for drone delivery services. The mailbox, in particular, should help to unlock the full capabilities of Pablo Air's drone delivery system.