I regularly write articles for magazines within my industry (Telecoms) and we have arrangements with a number of magazines that a certain advertisement budget will get us various article spaces throughout the year. These often appear to be objective insights into the way the industry operates, why certain products are good (ours), and why others are bad (all our competitors). It is nothing more than you pushing your own ideals.
I also spend an awful lot of time speaking with journalists, at conferences, and writing papers - these are all designed to get us noticed, and serve as a means to influence thinking. Journalists don't tend to know what their talking about, and are quite happy to regurgitate anything you feed them.
I would hardly think that the flying mag fraternity, nor their business models, are any different.