alt Hacker NewsMid-air: yes. A boom with a charging cable or even beamed energy would be much easier.
On the ground: swapping batteries is faster, and batteries are cheaper than planes or drones. You want the expensive part back in the air as soon as possible so you don't need as many of them. On the whole this probably also simplifies logistics: in civilian aviation airport space is limited, in wartime it's easier to transport one hundred drones and two hundred battery packs to the frontline than to transport two hundred drones
That's a future thought when it comes to electric aircraft - remote/emergency refuelling. I know they have tested lasers, and even sent a megawatt in 30 seconds over a distance of a few miles, though current convention of the laser back into usable power is around 50% efficiency. All gets down to a needed leap in electricity production and wished the World would get together on fusion reactors and knock it out the park over a mad race to be the first and lock down patents.