I think that would be a very good reason for these drones (in the case of the USS Kidd, testing our Aegis Combat System). But why leak these stories and videos to the public?
Perhaps, the Pentagon is just priming the Russians and Chinese with fake UFO incidents. When in fact, they are ours.
My honest if cynical answer is that quite a lot of fiction has been constructed about the stupidity of the unwashed masses, particularly the characterization of the superstitious hayseed evangelical deplorables (like myself). Leaking a story like this could both confirm that image in certain minds as well as giving crafters of narrative a roadmap for how the common people think about the unknown. Do they try to figure it out? Do they form a cult and worship the sky pyramids? Do they build underground bunkers and eat their spam by the light of bacon fat candles while wearing tinfoil hats?
https://www.militaryaerospace.com/sensors/article/14186795/hypersonic-drones-missile-defense
But why leak these stories and videos to the public?
I’ll play! We leak carefully crafted stories precisely because servicemen talk. The ‘word’ will get out anyway. So you leak a vague conspiracy theory first so that anybody with ‘real knowledge’ can be immediately discredited (because arrests and courts-martial are so messy).
Incidentally, the USAF Project Blue Book was great for covering up covert aircraft projects. Worked so well, the Russians were taking UFO’s seriously while we were overflying them with U-2’s.