Battery swapping and offline charging has not been successful in the automotive realm, but it might be a pretty reasonable alternative for aircraft. Even cheap aircraft are so expensive that the overhead of having two sets of batteries wouldn't make that much difference on the overall price, and you could probably rely on a shared pool of batteries anyway, since a lot of light aircraft aren't flown that much.

If battery swapping works then that also opens up some interesting possibilities like aluminum-air batteries that have much greater energy densities than lithium-ion batteries but which aren't rechargeable.