I'd go for the ad in a Dutch paper. It's their national airline and more people reading that paper would want a national airline they could be proud of rather than the cheap arm of AF. In the IHT most people who would see the ad wouldn't care unless they happened to be considering booking a KLM flight at the time.

We all have our reasons for flying KLM - for me it's because it's often less hassle to start a trip at LCY and connect through AMS than going direct from LHR.

Although KLM is my airline of choice, I'd certainly contribute to an ad (as long as the message was agreed on before donating) in order to make more people aware of the erosion in service.

Last time I donated to something like this was the Firefox campaign to get a full page ad in the New York Times, that seems so long ago. Oddly enough that was also around the same time that I took my first KLM flight.