I hadn't heard about the 3 fires thing until I started studying survival. Never heard about it in my pilot training.

I seem to remember it being briefly mentioned in my Canadian pilot training. But, if you go down in the bush, or get lost hiking, nobody is going to be able to discern 3 distinct fires from the air unless they are a long distance apart. Having said that, when flying over uninhabited country, any fire stands out for miles. A signal mirror combined with a fire would be very effective. At nignt, a hand held strobe would be your best bet as smoke is almost impossible to see in the dark from the air.

Your best bet for being found is to make sure you file an accurate flight plan or hikng plan with the appropriate authorities or a trusted friend who will alert the authorities if you fail to return. Up here in Canada, if someone is missing in the bush or a plane is down, pilots are alerted to that fact in their flight service weather briefing. If pilots know somebody is missing down there, they'll be watching very carefully over the area. If you can't make fire, you must get out into an open area...from the air, it's almost impossible to see through the tree canopy.