A method for automatically delivering a physical mail includes receiving, by an unmanned aerial vehicle from an unmanned aerial vehicle management system, a delivery information, the delivery information includes information about a first secure mailbox and information about a second secure mailbox, the first secure mailbox being related to a first target user, delivering the physical mail to the first secure mailbox, and rerouting the unmanned aerial vehicle carrying the physical mail from the first secure mailbox to the second secure mailbox in response to the physical mail being delivered to the first secure mailbox.