1) keyed propeller and

2) keyless propeller................... they have further classificaton

1.fixed pitch propeller

2.controllable pitch propeller

3.directional pitch propeller

Many small aircraft have 1 propeller.

A propeller is a wing. When the engine rotates the propeller, the curved surfaces of the propeller develop lift just as the main wing does. Since the "lift" is in a forward direction instead of upward, the aircraft is pulled forward. Surprisingly, the outer 1/3 of the propeller provides almost all of the lift pulling the aircraft.

How do you build a propeller

A propeller airplane is, simply put, any airplane which uses a propeller for propulsion.