Create a new edge along a face See the model below:



Is there a way to move the selected face without affecting the body of the plane? the wing was created by simply extruding the face, so now it shares the bottom edge of the wing and moving the selected face lifts body too.

Of course, I'd still want it to be connected to the body, i.e. the newly created edge should slide on the body face.

Edit

Here is what I wanted to do. Open blender, select default cube, go to edit mode and simply extrude one of the side faces (not top or bottom face) of the cube. You get two connected cubes (sort of). Now select the bottom edge that is common between the two cubes. I wanted to move this edge upwards (in Z direction), while keeping one of the cube intact.
Made it work. I just needed to go to Vertex mode and select the two vertices that join the body and the wing. Then from Vertex menu (Ctrl + V), choose Rip.