I haven't tried in Adobe AIR, but you can try setting the Boolean smoothing property on the Video object (see the videoObject:Video object on the videoDisplay skin part). You may have to fiddle with it to get it working in fullscreen mode though. You may need to create a custom skin.
I'll ask our video dev and see if he has any other/better suggestions.
I've added smoothing to the Video object of the new Spark VideoPlayer component whenever the AIR app enters fullscreen
Thought it would have been done by default as per the video player control in AMP.
Thanks for your help.