I don't know why "we" all tend to complicate this matter.
A smart person would NOT be building an airport or an ALA or a runway. A smart person is simply grading a paddock to meet the dimensional guidelines for an ALA as detailed by the CASA guide (if you want to be covered by your insurance), or any other suitable dimension if insurance is no concern.
You will then use that paddock on which to land and takeoff in your personal aircraft in exactly the same manner as you would build a road on your property to to allow you access with all your heavy equipment. Friends visiting you could use your paddock to land in the same manner they would use your private road on your property to gain access to you. Do you seriously need a DA to put a trafficable surface around your rural property and do you seriously need Council approval to drive your harvester, tractor etc across you paddock,? Do you need Council approval for a visitor to use your road into your property?
It is NOT a runway, it is a paddock on which you land and takeoff and as long as the paddock meets the ALA guidelines for slope and dimensions and has a means of indicating wind, your insurance will cover you and it is none of Councils business.
For God's sake don't tell anyone you are building an airport, because you are NOT.
It should be readily arguable that landing and taking off in an aircraft from your property is as much a normal rural activity for us as is driving a truck, tractor or car on and off your property. But please be sensible about flying right over your neighbour's house without their approval or they could make life difficult for you in the same manner as they could complain about driving down the road with no exhaust on your car.
Simple common sense folks ...
Building an airport is an entirely different matter and good luck attempting to get a DA approved for that ...