During every flight, planes switch to a mode where the engines work at zero leverage. If you are driving a car with a manual gearbox and switch the gear to neutral when going down a hill, it will be pretty much the same. It’s very rare that the engines completely fail to work. And even in such a situation, there is a way to launch the engines again.

But even without the engines, a plane can land. The most famous case was with a Boeing 747 over Java in 1982. The plane got into a dust cloud from a volcano that had erupted, and all 4 engines stopped working. The crew managed to land the plane at a nearby airport, and none of the 263 passengers were hurt.