The following article deals with the possibility of discovering several parameters of the picture when using Google Maps images, e.g. time and date of taking the image. This is possible with all pictures in which buildings, trees, poles ('objects') can be seen with their shadows. In some cases, one can find -- with a bit of luck -- an aircraft shortly before landing or shortly after take-off at a big and busy airport. If one detects such a situation, the question arises whether it is possible to estimate reasonably the actual height over the ground of the aircraft. The answer is 'yes', and we will show several possibilities; in one of them, the concept of three-dimensional similarity will play an important role.