The New York Times has a useful article about how airlines are using winglets — upswept ends of the wings of planes — to save money on fuel.
The Times article doesn't make the point that this is an example of what can be called free-market environmentalism, so I will. The airlines and aircraft manufacturers aren't adding these winglets because of some mandate by the federal government to reduce emissions or improve corporate average fuel economy standards. They are doing it to save money on fuel, and thus to give themselves a competitive advantage that allows them to compete for customers by charging lower prices or compete for capital by offering a better return (higher profits to shareholders). A central-planning approach would be for some lawmaker to pass the Environmental Preservation Through Winglet Mandate Act of 2013, requiring all airplanes to have winglets of some government-improved design by some date. But the free-market, knowledge-is-dispersed approach recognizes that even big companies like airlines or airplane manufacturers move quicker than the government does.
As the Times article reports, the different airplane manufacturers and airlines are experimenting with winglets of different sizes and shapes. The best designs have a better shot at winning, rather than, with the central planning approach, the designs that do the best at hiring former federal officials as lobbyists to require the adoption of their winglets.
Not every environmental problem can be solved this way; there's a price on jet fuel, while the price on other things, such as emissions or noise, is harder to measure and not always paid. But this is a great example of how the profit motive and environmentalism are not always at odds, and how they sometimes support each other.