Another alternative would be to acquire an organic AEW capability, but this would mean that the RAN and/or ADF had to acquire the additional AEW capability, plus the F-35B, plus allocate the funding to setup the trainings to use the F-35B, as well as establishing an ongoing programme to ensure that F-35B useage could continue by maintaining a stream of new pilots who can take off/land from a ship.
Further, if an organic AEW capability was introduced (along with the associated training and developmental costs to create doctrine, conops, etc.) sufficient AEW units would need to also be embarked, with these embarked aircraft requiring space at the expense of other units which would be otherwise carried.
I'm not sure organic AEW capability is really required. Australia has Wedgetails, with a nearly 7,000 mile range and refuelling capability, and short runway capability, could operate from Christmas Island, Butterworth or Lombrum/Manus base.
What we won't have is fixed wing fighters that are ideal for operating off Christmas or Lombrum. As we sell off the hornets to Canada (I can't believe they are actually going through with it), and the SH is few in number, mostly fitted for EW, and older are less capable not really directly deployable, and refueling platforms unable to operate off those shorter runways, you have a bit of a hole developing in the capability as we acquire these new far flung islands to project power from, but no platforms that can really protect them. They become obvious targets for an opposition to apply pressure to.
Any carrier task force is unlikely to operate outside of the range of our Wedgetails and P8's in any warm scenario. Let alone outside of JORN, sat, UAV and allied capability. Any of our Frigates, destroyers or Wedgtails can operate as a command and control centre and remotely fire and target weapons and sensor fuse with all assets in theatre. That is why we paid for CEC capability for all of these units.. In this case I think Australia is a head of the UK or say France.
The point about the number of ships is a valid one, and we flogged Bill and Ben in their amphibious role, and we are flogging the LHD's in their new found role. We don't have enough ship to support the desired ARG capability, even as a theoretical maximum. We haven't really got a great long term plan for the Army for its sustainable and expandable Amphibious training etc. We are still learning to walk amphibiously, but we have already outgrown our shoes.
Moving Choules along to some other role (like an Auxillary, like it was built to be) would create space for a third LHD (or similar, some aviation capable amphibious ship).
Now with three ships of that capability, you can deploy your ARG and support some fixed wing ops. Or be able to swing and provide some sort of majority carrier role, embarking 6-10 aircraft and a reasonable sortie rate for a short period some distance from one of these more forward island posts. Enough that other assets (from Guam, or mainland Australia etc) could support act and fill in the space.
Airforce wants 100 F35's. The only way I can see them getting that 4th squadron of manned fighters is through something jointly supported. Forward deployed off the islands and with a portion embarked on 1 LHD continuously. Its in the vague realms of possible.
But this is years and years off. A new ship is probably a 5-10 year deal. You would probably want more P8's and Wedgetails and have that northern navy base built. You would want the subs to be really underway and secure. You would want the US and UK do really have the F-35B sorted and having a regional partner like Japan throwing in too would be helpful. Our F-35A should all be FOC. The Tigers are a higher priority for something armed to fly off the LHD's. Probably want more Romeos too.
If your putting together 10-20 year plan, then there are elements that can be pulled together before committing to big specific items like the airwing itself.
