The following methods will allow you to do your own typical S.O.S signals. Ground-air signals We can make a huge sign on the ground with any elements that strongly contrast with the background and therefore is clearly visible from above. For example we can write a clear "SOS" on a green meadow, we can prepare the signal digging a pit and keep the earth piled up at the edges to increase the shadow's effect. To be perfectly visible from the air, letters or symbols that we use ought to have at least 10 meters high and a separation of about 3 meters. Signals mirrors On sunny days, We can use a mirror to make effective signals from many kilometers away, but we must do it correctly. We need a reflective surface on both sides, like a piece of tin with a bore hole in the center. Looking through the hole, We will point then to the spotted airplane in the sky with our makeshift signal mirror. In the reflective side facing us we would see the point of sunlight coming through the hole and is reflected in our face or our clothes. We must now move the mirror to fit onto the hole's positionof the reflected point without taking your eyes off the airplane. Simple flashes will draw the attention, but will be more effective if we transmit the signal in morse code that are three straight points, three stripes, and three points again: "... --- ...". Smoke and fire signals Fire is one of the best ways to reveal our position to anyone. We should take into account that three equal signs, of whatever kind, will always be interpreted as a message of SOS; so if we have enough fuel to make three fires. We should then prepare three piles of firewood in a clear place and near our camp, the three bonfires have to be ready for kindling. We must prepare plenty of tinder for the bonfires in order to ignite them easily and quickly. To help ignite them we can impregnate a cloth in gasoline and add it to the tinder, but never put any flammable liquid directly to the fire, because of the risk that the flames would reach us. The Night is better time to see the blazing flames, but during the day the smoke is more visible. We can obtain black smoke from burning engine oil, wheel's rubber or other objects. For white smoke can be obtained from burning leaves, green grass, moss etc. The black smoke is visible and cloudy days , tundra or in the desert; white will be more visible in a forest or during clear days.