Air View lets GS4 owners preview content just by hovering their finger above the screen. For example, you can see what photos are in a folder by expanding it or you can preview the contents of a message in the Email app. However, Air View can drain your battery because the phone needs to calculate whether you're trying to touch the screen or hover, and even then the feature can be erratic.
To disable Air View, swipe down from the top of the screen and tap the Air View button in the Quick Settings options that appear. Or you can head to the Input and Control section of the My Device tab within the Settings menu.