Every PowerUp 2.0 - Electric Paper Airplane Conversion Kit, includes a spare propeller.
The PowerUp 2.0 was intentionally designed as a pusher style prop also providing extra protection to the blades while spinning. In PowerUp 2.0 we changed the plastic formula of the propeller, now it will never break. Never-the-less after many crashes propeller could get loos and fall off, if you lost it, you can assemble the spare propeller. In some instances the propeller may touch the ground after landing and over time this could gradually chip the propeller, eventually this may degrade the propeller performance, in this case you may need to replace the propeller.
If you damaged both included propellers you can purchase a spare here
How to replace your PowerUp propeller...
First remove the damaged propeller. Pulling the propeller with your fingers could accidentally extract the entire motor and permanently damage the entire power unit. Slide a flat screw driver between the motor and the prop, rotate the screw driver to extract the plastic prop out of the motor shaft.
Before assembling the new spare prop, identify the correct orientation of the prop, remember that this is a pusher prop, the concave blade must face the back edge of paper other wise you will not get sufficient thrust for flight. Carefully align bore to the shaft and carefully slide into place pressing with your thumb on the center of the prop.
Leave a tiny gap between the mount and the propeller. Propeller must not touch motor mount while rotating. if you need to adjust the gap use the screw driver.
Now you are ready to fly your Electric Paper Airplane.