Curious note just discovered on NZ135 headed over the Tasman (not as curious as the 15 hour NZ29 not having it but the 3 hour NZ135 having it ... sigh)

Appears Apple Music works on the inflight wifi even before selecting a plan - which suggests that even when chargable, you’ll still be able to use it for free (which I highly doubt is intentional, as unlike Qantas who actively encourage use of inflight wifi to access streaming entertainment over the plane’s IFE library, NZ discourages it as UA does).