Looks like he just discovered that he could fly!
(I got this set of pictures from some website somewhere a long time ago, the owner of these pictures had posted in the comments. All rights go to him at - www.jpixphoto.com)
(However, I'm keeping these pics on my flickr stream CC licensed as that brings more traffic, which in turn should bring more traffic to Jasen at JPix Photography. Disclaimer: I'm in no way affiliated with JPix, my dog is a Maltese as well and I only stumbled on these pictures online somewhere.)