Good points all, except i've got to disagree with one. While the Aeroclub is less crowded still go to the museum.
They get your $15 support (absolute bargain for what you get and bloody well earnt by the museum). Plus it's all on right in front of you. I arrived about 10am and got a great seat on the fence line easily.
Come on, if you're gonna enjoy what has got to be Australia's best aviaition museum then at least SUPPORT IT!!!