One last short note about finding possible ancient sites from above…
Scientific tidbit de jour: all bodies emit radiation. This radiation is in the infrared range. Just like in the Predator movies, how the extraterrestrial alien sees the humans glowing in the dark. The alien is picking up infrared radiation emitted by the human bodies. The wavelength (similar to the colors) of the radiation being emitted is dependent on the temperature of the body. That’s why the infrared image of a human body shows different colors between the torso area and the extremities, since the temperature of the torso is at a higher temperature. Not only living bodies emits infrared temperature, non-living objects emit radiation depending on its temperature as well.

Now going back to the previous message on the difference of temperature between the spot that has ancient structure underneath and areas that don’t (under certain condition), one would get different infrared radiation from them. By taking a infrared photograph from a plane (need to have a VERY good infrared camera, meaning a very sensitive camera, since the difference could be very small), one could pick out certain area with higher probability that some “interesting objects” are underneath it by looking at the different infrared “colors” in the photograph.