You don’t change altitude frequently enough and even if you could recover 80% of the energy you spent on reaching cruising altitude when you perform your landin

You don’t change altitude frequently enough and even if you could recover 80% of the energy you spent on reaching cruising altitude when you perform your landing approach it won’t be much, and probably won’t be worth the extra complexity and weight of an energy recovery system. Unless we’re talking about very short flights the majority of your energy would be expanded at cruising altitude especially since electric engines have a fairly flat efficiency curve.