Yup. Air as a means to power a sailboat is about the only way it works.
Still takes gas/coal/nuke to compress the air otherwise and that WASTES energy. Far more efficient to use the gas/coal/nuke directly. AND less polluting because of it.
Perhaps if the compression cycle was integrated with
braking, then useable energy could be recovered and
used again. ??
But carrying around an engine big enough for decent acceleration is also inefficient. A smaller engine for cruising plus the hybrid system to give a kick to acceleration can be more efficient than a big engine.