I just found it out on KLM website
http://www.klm.com/travel/nl_nl/spec...=nl&intlang=NL
You click on the GlobeAssistant button and, provided that Google Earth is installed, all airport served by KLM are displayed, with the lowest fare from AMS.
It would be nice to have more options, such as seeing schedules, availability, prices and routing directly from Google Earth (something like "from here ... to here...").
What do you think?