1. An unmanned aerial vehicle (UAV) authorization system for authorizing a pilot to operate a UAV, the system comprising: a UAV controller device; and a control authorization unit comprising a processor, a communication interface and memory, and which is in communication, via the communication interface, with the UAV controller device that is in turn in communication with a UAV, said control authorization unit further comprising, an authorizer operating on said processor for, receiving an identification code from the UAV controller device that was entered into the UAV controller device by the pilot, transmitting the identification code to a digital certificate storage unit, receiving a signed digital certificate from the digital certificate storage unit whenever the identification code corresponds to the signed digital certificate, determining if the digital certificate is signed by a trusted signatory whose signature is in stored in the control authorization unit memory, and whenever it is determined the digital certificate is signed by a trusted signatory, deeming the pilot to be authenticated, and whenever the pilot is authenticated, transmitting a validation request to a validation service to determine whether the digital certificate is valid, wherein said control authorization unit is in communication with the validation service via the communication interface, receiving from the validation service, a validation indicator indicating whether the received digital certificate is currently valid, and whenever the received validation indicator indicates that the received digital certificate is currently valid, authorizing the pilot to initiate control instructions via the UAV controller device and attaching the signed digital certificate to any control instructions initiated by the pilot.