Yes. Sort of.
During the testing for the Manhattan project, the explosion could be heard for about 100 miles. Aircraft can carry comparably-sized bombs, so aircraft can play sounds that can be heard that far away.
(Someone might be tempted to object that an explosion doesn't count as "playing" a sound. To that person I would say, 1812 Overture.)
But to answer more specifically to your scenario: Sort of. Roughly, a 52,000m distance (50km over and 15km up) is two to the 16-and-a-bit, drop-off is about 6dB/doubling, so you get about 100dB of dropoff. Here is a quick description of a 165dB speaker someone made (Why?!). That leaves you something like 65dB of sound at 50km. Which is a lot, about like the volume in a crowded restaurant.
Weight-wise, that trivially fits on a plane. Where your plan will run into problems is intelligibility.
On PPE: cutting-edge modern man-mounted technology can only make it safe up to (very roughly) 130 dB. It's a problem. Anything above that you would need to deal with by soundproofing the cockpit. You likely need about 40dB of very, very serious isolation. Remember, this requirement would be in tension with the need to attach the cockpit securely to the aircraft frame. It's probably doable, but far from trivial.
Lastly though, just because something is technologically possible doesn't make it a good idea. Think about what that side is trying to actually accomplish (seize land, favorable trade deals, etc.) and consider how this tactic supports that strategic objective. If it doesn't support their war objective, the side using it is hurting their own cause.