Fast Jet, Multi, Helicopter; they all have one thing in common, they fly! UAVs fly also, but their crews do not. The crews of Fast Jet, Multis, Helicopters do fly, and therefore they are aircrew, including their cabin crew (though not many in FJ I'll allow). By classing RPAS crews as aircrew and denying that classification to those who do fly in constituted flying crews is illogical, cruel, and I suspect based on snobbishness.
It has been said rightly that the origins of RAF aircrew began with such snobbishness but in the end the RAF had to bite the bullet. Time for it to do so again. Why? Because the purpose of Cabin Crew is to safeguard the lives of their passengers, be it in the air or on the ground. Without being eligible for a Flying Badge they are seen by some as mere airborne waiters and waitresses (their secondary role) and so the authority they need to ensure compliance to their instructions in emergency situations is much diminished. Be they SACs or Cpls, they must be in charge when evacuation, donning oxygen masks, donning LJs, remaining strapped in, or simply attending to their safety briefs is called for.
The Military Air Regulator, the MAA, says they are aircrew but the Military Air Operator, the RAF, says they are not. Yet another indicator of the ambivalent attitude prevalent in the modern RAF to Air Safety!