A rotary UAV is more plausible than a helicopter-carrier submarine

Is a helicopter-carrier submarine a useful idea?

Not as a crewed helicopter carrier, though launching a compact rotary uncrewed aircraft could be worth exploring.

A helicopter-carrier submarine is unattractive, although a submarine-launched rotary-wing uncrewed aircraft remains plausible. The distinction moves the problem from supporting a crewed aviation detachment to deploying a much smaller remote sensor or vehicle. The idea remains speculative, but it identifies a narrower mission that fits submarine constraints more plausibly.