[smolder]

Hybrid tech doesn't help at all with with planes. There is no braking energy to be regained and batteries are too heavy. It has no place there until battery energy density approaches that of fuel, which would require a huuge breakthrough of some kind.

[Reason077]

The idea behind a hybrid aircraft is that eFans (electric fans) are more energy efficient than a turbofan, so you can burn less fuel for a given journey.

Companies including Airbus, Siemens, and Rolls Royce are actively working on this technology with a view to have working prototypes in the early 2020s.

Besides that, there is some "braking" energy to be recaptured during descent or when slowing the aircraft. This technology already exists today: The Pipistrel Electro can regen it's battery during descent. This is similar in principle to the ram air turbine (RAT) in conventional aircraft.

[smolder]

Well thanks for the pertinent info. I was pretty sure of myself that the cost benefit ratio wasn't there but if there are engineering efforts towards it there's at least potentially some merit.

I wonder, does the efficiency gain from efans and a generator apply to a single engine setup as well as it does to multi engine setups?