Air walkers and elliptical cross trainers are very similar. Both involve a cyclical stride, where you press your feet forward and back. And both (typically) include moving handlebars you can grip to move your upper body, too.  That said, ellipticals tend to be larger and bulkier than air walkers. Ellipticals come attached to sturdy bases that ground the machine, helping you stay balanced. And since these bases often come equipped with electronic technology, you can use them to scale your machine’s resistance level up and down. Air walkers tend to be much lower-profile. Their pedals aren't attached to bases, which means you may have to do more work to stay balanced. (This also means you can rarely scale the resistance of your glider workouts up or down.)  Finally, some air walkers are designed to let you move your feet out to the sides—in addition to sliding them forward and back. Since ellipticals are attached to firm bases, they don’t offer this 360-degree range of motion. (It’s worth noting that many gliders don’t offer this range of motion, either. So if you’re interested in this, you’ll have to seek out a very specific style of air walker.)