> Hybrid cars work mainly by recovering energy from braking or going downhill to charge the batteries.
While hybrid cars do those things, they aren't the main source of the efficiency of parallel hybrids, parallel hybrids like the Prius work by keeping the engine at the most efficient throttle setting (which is much higher than what would normally be used for cruising) whenever it is running, and using excess power from the engine to recharge the batteries.
The article describes this aircraft as doing the same thing.
While hybrid cars do those things, they aren't the main source of the efficiency of parallel hybrids, parallel hybrids like the Prius work by keeping the engine at the most efficient throttle setting (which is much higher than what would normally be used for cruising) whenever it is running, and using excess power from the engine to recharge the batteries.
The article describes this aircraft as doing the same thing.