Amazon has filed a patent for flying warehouses that could use a fleet of drones to make deliveries to customers. A patent document filed in 2014 in the US describes giant airships as "airborne fulfilment centres" (AFCs) that could be stationed above metropolitan areas and used to store and quickly deliver items at times of high demand, using drones dispatched directly from the airship. The technology and e-commerce giant is already testing drone deliveries in the UK, and made its first commercial delivery under the trial in Cambridgeshire this month. The patent filing also suggests smaller aircraft and other unmanned aerial vehicles (UAVs) could ferry workers to and from the ship as well as replenish stock. "The AFC may be an airship that remains at a high altitude (eg 45,000ft) and UAVs with ordered items may be deployed from the AFC to deliver ordered items to user-designated delivery locations," the filing reads.