Owls' bodies up optimised for silent unpowered flight, and even when it is powered flight, it's powered by wing flapping (rather than jet engines or turboprops). At most I suspect you'll be able to help silence the noise from a body passing through the air; as gliders are rather quieter than light aircraft, I suspect this is the minority of the sound, at least until speeds get very fast where the aerodynamic and acoustic models will be very different anyway.

However, as "aircraft" is widely defined, perhaps they would be useful for a drone that for portions of its flight mostly glides silently at low-ish (owl-like) speeds, for covert photography, covert small payload delivery, or some other likely nefarious purpose. Heck, it could actually be disguised visually as an owl.

Owls' bodies are optimised for silent unpowered flight; even when owl flight is powered flight, it's powered by wing flapping (rather than jet engines or turboprops). At most I suspect you'll be able to help silence the noise from a body passing through the air; as gliders are rather quieter than light aircraft, I suspect this is the minority of the sound, at least until speeds get very fast where the aerodynamic and acoustic models will be very different anyway.

However, as "aircraft" is widely defined, perhaps they would be useful for a drone that for portions of its flight mostly glides silently at low-ish (owl-like) speeds, for covert photography, covert small payload delivery, or some other likely nefarious purpose. Heck, it could actually be disguised visually as an owl.