Was the single-engine fighter in World War II started by a hand propeller? How does a large plane with two engines or even four engines start?

This statement is wrong. It has nothing to do with the propeller. This is the way to start the internal combustion engine. If your car stalls, it will be started by manually driving the engine piston to reciprocate from the outside, but it is usually started by a normal battery-powered spark plug. Therefore, you will see that the ground crew started the engine in this way, which is essentially the same as the current hand-cranked emergency starting vehicle, except that there was a similar starting battery at that time, and it was not needed in many cases.