Here’s a really cool app called Hovering Controls App, that allow you to add hovering shortcuts to any Android smartphone similar to the Air Gestures found on a Galaxy S4.
This app uses your proximity sensor to detect your swipes over the phone and works quite well in allowing you to open up custom apps using a single/double swipe or even browse your Gallery and Browser using swipes. Also, you will be able to answer calls easily simply by holding your phone to your ears.
Overall, this is an awesome alternative to owning the Galaxy S4 and works just as well (maybe even better) than the original Air Gestures. I’ve also found out that it works in complete darkness.
If you need Air Gestures on your Android smartphone, definitely try this one out and do let me know what you think!