This article provides interesting information on subsidies to small market airports. I've always thought that many small cities wouldn't be as economically attractive absent these types of subsidies.
More importantly though, I think that these types of relatively minor issues offer activists a good opportunity to argue for the proper principles and illustrate them in a very concrete and therefore understandable way. (Not that I think the author of the piece does that.) They also have the distinct plus of affording activists an opportunity to "win", since in a limited issue like this one, one can make one's voice effectively heard and significantly influence the outcome.