Just go to the main page for Airliners.net. Find the section for Most Popular along the left hand side. Click on "Of All Time". It seems like this is the most popular of all time with over 100000 views:
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Photo © Samuel lo
Another way to do it is to scroll down to the section for the Aviation Photo Search Engine but don't type in anything or select anything. Under "Sort by" select "Most Popular Photos First" and then click on "Show Me the Photos". You can make variations on this by putting in the name of a photographer or an airport or a plane or airline and you can see all the photos meeting those criteria and ranked with the most popular ones first.