Sometimes your survival scenario will leave you without a radio, means to build a fire or anything shiny you can use as a signal mirror. In this case you need to be familiar with some hand and arm signals in case a rescue plane or helicopter is overhead. If you see a rescue plane overhead and it's close enough to spot you, simply hold both of your arms above your head. Waving them back and forth is probably your first instinct, and while it's not the official signal for rescue, it would most likely send the appropriate message. If there's an area where a helicopter might land nearby, get into a squatting position and aim both arms straight out toward the clearing. If it's not safe to land where you are, keep both arms together and wave them over your head. There are many other hand signals that military personnel are taught, but indicating that you need help and advising on a place to land should be enough in a civilian rescue scenario.