Planes have a much larger surface area to carry solar panels, and they fly above clouds, so have clearer access to sunlight than cars do.

Wind charging is more of a pipe dream, but there's no reason a plane couldn't glide for a period of time to get some energy back, similar to regenerative breaking.

There have been experiments in both areas, and while it's certainly unfeasible today for any large aircraft, the technology and efficiency will only improve. It would be wrong to discard these as an impossibility.