In the future, drones will deliver our packages. Amazon is already working on such a system. Prime Air is a future delivery system that will rely on unmanned aerial vehicles to deliver packages in 30 minutes. These drones fly under 400 feet and weigh less than 55 pounds. They will have multiple redundancies and sense & avoid technology.
These drones are able to deliver packages up to 5 pounds. The system is not ready yet, but it is nice to know Amazon is working on it.