The regular 17 is cheaper than the Air, not more expensive. And it has a better camera and battery and a slightly worse processor (but still better than the 14 there). The next gen Air might be worth getting but the current one is an awkward model that only makes sense if you want it for its thinness. It is $200 more than the plain 17 with only one better feature (processor) other than thinness and $100 cheaper than the Pro which has a lot of improvements (battery, camera, screen).

In most of Europe the Air is cheaper than the 17.

The 17 Pro also has the benefit of the aluminum housing.