Device, system and method of protecting aircrafts against incoming threats. For example, a system for protecting an aircraft against an incoming threat includes: one or more electro-optic sensors to substantially continuously search for the incoming threat, and to generate a signal indicating that a possible incoming threat is detected; one or more radar sensors to be activated in response to the signal, and to search for the incoming threat; and a central computer to determine whether or not the incoming threat exists, based on a sensor fusion algorithm able to fuse data received from the one or more electro-optic sensors and data received from the one or more radar sensors.