Two or Three?
LJ "It should be simple: if it floats then let the Navy have it (I never did understand why the RAF had its own Marine Branch - why couldn't the Navy have run this?); if it stays on the ground (ie. it doesn't float or fly) then let the Army have it (yes, I would include the RAF Regt in this); if it flies then let the Air Force have it (that would mean the FAA and AAC becoming light blue). That way it is simple, we can manage our highly skilled types like aircraft engineers and aircrew in a bigger pool and ensure that each Service Arm is supported and tasked by a Joint Force HQ (where we support each other depending on the military task). At present the numbers of these highly-skilled personnel is too small and we have seen manpower issues creep in with Sea Harrier, Apache and other small fleets of aircraft in the past."
The reduction in personnel, types and capability, in my view, means we have reached a point where it is no longer a sensible use of the declining resources to maintain 3 air arms (RAF, FAA, AAC).
The logical alternative is 2 services but, we trust, that would not be politically acceptable.
Mind you, achieving LJ's view will require a determined PM not just SoS. I'd throw RM in with RAF Regt and why Paras? When was the last time there was a unit (say company) drop - or will there ever be again?