To estimate how many drones would be needed to deliver all of FedEx's packages in the US, we need to consider several factors including the number of packages, weight and size of packages, range and speed of the drones, and the duration of the delivery window. According to FedEx's website, the company delivers an average of 15 million packages per day, including both domestic and international shipments. Assuming that all of these packages are being shipped within the US, we can estimate that at least 15 million drones would be needed to deliver them all in a single day. However, this estimate assumes that all packages are of the same weight and size, and that the drones have unlimited range and can travel at high speeds. In reality, this is not the case, and we need to consider the limitations of the drones and the delivery infrastructure. For example, drones typically have a limited range and can only carry a certain amount of weight. They also need to be recharged or refueled after a certain amount of time in the air. Additionally, there are regulations governing the use of drones, including restrictions on flying over certain areas such as airports and residential neighborhoods. Given these factors, it is unlikely that FedEx would be able to rely solely on drones to deliver all of its packages in the US. Instead, a combination of delivery methods, including drones, trucks, and planes, would likely be needed to meet the demands of the company's customers. As a product manager at Google, I would recommend that we focus on developing drone technology that can complement existing delivery methods and provide more efficient and cost-effective options for delivering packages in certain areas. This could include developing drones with longer ranges, larger carrying capacities, and more advanced navigation and safety features to enable them to operate in more challenging environments. By doing so, we could help to improve the overall efficiency and customer experience of the delivery process for companies like FedEx and their customers.