Physicists have actualy calculated that for human-powered flight (ignoring the magic/tech), a 70kg superhero would need to generate roughly 100-200 watts of continuous power just to hover, and exponentially more to achieve those ridiculous accelerations we see in movies - you’d need caloric intake that would make The Flash look like hes on a diet.
The simple answer is always antigravity aka magic. You could calculate the force of gravity acting on them and say that amount of antigravity plus the force required to accelerate them at the rate they accelerate including wind resistanceat the elivation they are flying, but you would need their mass and dimensions.
I think you’d first have to have a biological explanation for how they can fly before you determine how much energy it takes.
Or the physics explanation, straight up 100% efficient gravity control would be less than walking up a similar sized mountain (conservation of [potential] energy). Something using zero point energy to force could be net positive, it depends…
It doesn’t take any energy to fly, if you’re made of helium.
