A method for allowing missions of unmanned aerial vehicles (UAV), in particular in non-segregated air space, includes the steps of: prearranging a flight plan by an operator of an unmanned aerial vehicle; verifying, by a management and control body, that the flight plan is compatible with other flight plans of other aerial vehicles, and, if necessary, modifying the flight plan so as to prevent any collisions with the other aerial vehicles, wherein the following steps are carried out: encrypting the flight plan, by the management and control body, with a private key of the management and control body, so as to obtain an encrypted flight plan; encoding the encrypted flight plan with a public key of the unmanned aerial vehicle for which the flight plan is intended, so as to obtain an encrypted and encoded flight plan.