If you want to display your model aeroplane as though it were in flight, a static propeller does not look quite right. You could try to locate a DC micro-motor and extension shaft, install that and attempt to conceal the wires and a battery pack in the display, but this is nearly impossible to do for many planes due to space restrictions. The other option is to create the propeller effect with a plastic disc, a much simpler task.
Locate a stiff sheet of clear plastic approximately 1mm thick. Waste packaging is a good source for this.
Measure the diameter of the propeller supplied with your model kit. This will be the diameter of your disc.
Use a compass to draw a circle on the plastic equal to the diameter of the propeller.
Cut the disc from the plastic sheet with the hobby knife.
Place the propeller from the kit onto the disc and mark the location of the shaft and tips of the propeller.
Draw an V shaped cone like the opening of a bugle or vase from each propeller point on the plastic disc with the wide end toward the top of the disc.
Remove the bugle-shaped sections from the plastic with a hobby knife.
Clip off each propeller approximately 1/3 of the length up the shaft into sharp, centred points.
Glue the blades cut from plastic sheeting to the backs of the propeller blades.
Paint in each propeller blade with short, tight, zigzagging horizontal strokes, gradually widening the stroke to match the blade dimensions. The effect should be a feathered look, especially at the top.
Feathering, or blurring, occurs most prominently at the top of the blade. This part will appear more extended and sharper. For an even more realistic effect, you can feather the propeller blades with a hobby knife. If you have an airbrush, use it to create the blurred effect for additional realism. Most propellers are black, but if your plane would have a different colour, that is what you will need for your blurred effect discs.
Don't glue the nose cone on until you are happy with the final product. It may take a few attempts to get this the way you want it and it will be easier if you can move the nose cone.