Summarize the article about the use of drones for delivery.
Drone startup, Wingcopter, has completed a successful drone delivery trial, in partnership with Merck and the Frankfurt University of Applied Science, covering a 25 km distance, transporting pigments from one lab to headquarters in Germany. The flight covered a dense metropolitan area without continuous line-of-sight. The trial demonstrated the benefits of using drones instead of trucks for small cargo, saving time and reducing emissions. The successful flight could serve as a blueprint for other similar pilot projects, and the partners plan to release a report summarizing their findings in March.