Re. capacitors
Maybe this could be just the thing that microdrones (yes this is actually a real thing) need to take off.
Picture this, a whole army of these things which when the battery gets low seek out a convenient metal immobile object with the correct magnetic properties and "clamp on", extending their shielded solar panels mounted on the rotors to capture sunlight like a leaf.
Upon fully recharging they exchange information to each other like "Hi Drone 455, there is a nice landing point here" and any other useful information then apply current pulse directly to the magnet via resistive contacts to weaken the field enough to detach then resume their SAR/etc mission.
Also an advantage with microdrones is that if they are equipped with a hive mind they can cooperate on tasks such as linking together via magnetic (alternate) clamps and lifting large objects.
Sort of like foglets but on a larger scale.