But the most important fact that seems to present itself from the graphic - is that all the hard work and regulations of the past decade has worked! The higest level reached is only 72dB and is directly (as far as one can tell on this large scale graphic) at threshold.
No, you are misinterpreting the graphic.
Those are not point dB values, they are simply the keys to the shaded areas on the map, which are the recently-published 2012 Noise Exposure Contours (that's why those Leq values are spaced at 3dB intervals).
They don't represent instantaneous or peak values from individual movements or airlines.