Sell a storage system that allows the batteries to be safely and individually stored and integrated. It could estimate the capacity of each battery and house 20 or so. Such a system could probably pay for itself after using it for less than a year. There are certainly going to be guaranteed minimum capacities that such a system could promise, it doesn't need to be perfect. If enough people invest in such power storage systems, you don't need to have a single system work 100% of the time, just like you don't need every wind turbine to work 100% of the time.
There is some scope for winged humans, and hypothetically some capacity to exercise it. Nature did not explore this route. The opportunity cost of exploratory settling into a non-preferred niche usually outweighs the benefits of that exploration simply due to the scarcity of available resources to buffer against the opportunity cost.
But, as noted, for this case there is very little in the way of cost.
Nature did, in fact, explore the winged-bipeds body plan to full fruition twice, once in mammals, and did winged quadrupeds before and again in mammals. She is progressing on a another as I write this. And, humans did end up conquering the air without growing wings. Nature isn't picky about methods.
I don't understand the recent push to ascribe consciousness to trees. An anesthetized human being has many more allostatic and homeostasic mechanisms than a tree, and yet we don't ascribe consciousness to anesthetized humans...
