Hold down control, use the scroll wheel of your mouse (or two finger swipe up and down on your trackpad) – voilà. ;)

Oh, my god - this is bad.

As a flight sim buff, I'm suffering from the current dearth of good flight sims, so JASA was bound to catch my eye - despite the appalling web site. Unfortunately, sometimes the first impression is right. JASA is simply *bad*. The graphics aren't even up to early 1990's standards, the flight model is a joke, the controls imprecise and weird, maps, planes and missions have no relation whatsoever to "Afghanistan" and in five minutes playing, I found a handful of gamebreaking bugs (key commands aren't displayed in the tutorial, enemies don't turn up, missiles aren't fired).

Keep away from this crap.