I guess you could think of a hovering helicopter vs a circling aircraft, both having the same weight and hence same lift. Both have to accelerate some air mass

I guess you could think of a hovering helicopter vs a circling aircraft, both having the same weight and hence same lift. Both have to accelerate some air mass downwards. The lift comes from the velocity x mass = momentum of air, which has to be the same with both. Since the airplane wings affect a larger air volume than the helicopter blades, the airplane accelerates a larger air mass, but to a lower speed. The helicopter: smaller air mass, higher speed. Since energy required is proportional to the second power of speed, the helicopter requires more power for the same lift. You could create a helicopter that was quite efficient in hover, with really big blades. It would then have some other problems, like limited speed.