The following photos will give an idea how to build a comparable mobile but you will have to use your own scrounged gear so I won't go into real specifics.
Step 1: Make an airplane, attach motor and boom
The following website provides some really neat planes that can be made from cardboard in black and white and color. I chose the Spitfire.
Attach the motor to the plane. I used a cable tie to do that.
Find a toy propeller from one of those broken airplanes we all seem to have and attach to motor shaft. I drilled a shaft size hole in my propeller and attached with super glue.
Then you must attach the plane to a boom approximately 4 feel long and of any kind of material.
I used a piece of hollow fishing pole. Again I used zip cables to attach the plane to the boom.
Run the two wires from the motor inside the boom (or outside if you wish).