Control a PC with Air Gestures I'm aware of a few questions that talk about controlling a PC with an Android phone:  


control android device from pc
https://android.stackexchange.com/questions/2925/is-there-an-android-application-for-remote-control
How to Remote Control Android smartphone, if not in same subnet
How can I turn my android phone into a remote control (mouse/keyboard) through bluetooth for ubuntu/linux


Is there any support for Air Gestures of the Galaxy S4 in any of these products? I would love to place my phone on table during a presentation and wave my hands around to magically advance the slides.
If you take a look at the Air browse feature under Air Gestures, you will see that it is limited only to the following applications:


Gallery
Internet
Music Player
Music on lock screen
S Memo


So NO, you can't use it for presentations.