Good, tesla looks like a shit.

Good.

Helium could be detected with some specialized detectors, but I suppose approximately – so, as you said, finding exact leak place is challenging.

Helicopter can also go into autorotation mode, i.e., to “gently” land even with engine failure. I think airships has no moving parts, what’s safe, and with the gas leak, I think it is rather slow process, so it would be easy to gently land.

Good.