Then, have you not heard of the ACT Government's Environment, Planning and Sustainable Development Directorate?
Whether you want to build a house, factory or Airfield the primary decider on whether it can be done on a property you select will be Planning status.
Step 1 is to select a suitable property you think would be ideally located, with suitable weather conditions and meet the technical requirements for an ALA etc.
Step 2 is to go on the EPSDD site punch in the property address, and get a property report and map of the property.
This will show the Zoning of the property.
Step 3 is to read through the Uses for that Zone.
They may be split into three groups;
1. Permitted Uses without a planning Permit. This may include "farming", something like a tool shed on a farm with a size not more that 10 sqare metres
2. Permitted Uses requiring a Plannning Permit.
This would be where you start looking for "Airfield"
3. Prohibited Uses
These usually include Motor Racing Tracks, and may include Airfields, making a decision on the property easy; go to the next property.
If you find a property which allows a Use of Airfield, you then provide a Development Application (DA) to the Local Government Authority for approval.
Anyone can submit a DA, however for an airfield I would recommend hiring a qualified Planning Consultant. These people have done 5 years Planning study at a University and know their way around the very complicated system.
You particularly don't need a politician or public servant, or need to know someone.
As you can see from this process it's relatively easy for someone to identify land suitable for an airfield, buy it and, where it meets the Planning Scheme for that area, get approval to build one with private hangars etc. obtaining Planning approval for these items where specified.