[lawrenceduk]

Pilot here, I don’t think this is right.

Aircraft typically operate at 80-100% power output. It’s not the average 20% power output of your car.

Weight is pretty much everything, the savings from regenerative braking in an aircraft are almost 0% but the cost of enabling it is some tons.

This tech makes loads of sense in a car but I’ve never flown an aeroplane in stop-start traffic because that’s not how the sky works.

[wkat4242]

Indeed and an aircraft never really 'brakes' like a car does, except for 20 second on the ground (including thrust reversers). Even in a descent you would have significant forward thrust. The drag does all the braking. And you can't regenerate that.

PS I'm a hobby pilot so please correct me if I'm wrong but I don't think even an airliner would idle their engines during descent.

[pfdietz]

I don't see how that can possibly be correct, at least for commercial airliners.

An airliner will use maximum power at takeoff, somewhat less for climbing, and much less during cruise. The figure I see is takeoff fuel consumption/hour is like 3x cruise fuel consumption/hour. Power needed will also decline as fuel is burned off, since the required lift goes down.

[unyttigfjelltol]

Thinner air. Engine is not capable of burning as much fuel, or generating as much thrust, with full performance at cruising altitude.

[pfdietz]

Ah, that explains it. Thank you.

[XorNot]

Couldn't this just be related to relative engine efficiency? You could easily be running the engines effectively full power the entire time, but obviously high-altitude cruise is where you spend most of your time and presumably the engine's are optimized for that operating regime.