How do I make my player sprite "pushing" an other sprite

Here is my problem :

Since my player is "flying" in a platform environnement, I use "8 direction" behaviors (when no key is down, the player doesn't fall). I need it can push some other sprite affected by "physics" behaviors. All my tries with "physics" or "solid" behaviors are fails. I guess I need some example that makes me understand how to do it.

Where can I find informations about "player sprite making move another sprite by pushing it", at least in a classic platform style?