It is a hard call, I love the RAAF Museum at Point Cook its Australia's premier collection on Australia's most significant Aviation Heritage site (athough Defence will not permit you to enjoy and view much of the sites most important buildings!), and the B-24 is nearby making a Point Cook/Werribee visit an excellent combination.
Moorabbin's an excellent visit too but of course not quite the same presentation as the RAAF Museum, but you can get up and close at Moorabbin as against behind the rope or mesh fence so both are worth seeing in my view.
Moorabbin is open from 10-5 Saturday and Sunday, and Wednesday, Thursday and Friday from 12 to 4pm.
If you are coming on the weekend of 2-4 October I would recommend trying to get to Moorabbin as we have our Wings and Wheels exotic car show on, with over $3M of exotic Bugatti's on display from sloops to GrandPrix racers. - there is a higher entry price reflecting the rare car show, but well worth seeing, and on Sunday 3/10 we have a running Merlin, Cheetah, Heath-Scott and Rover Turbine to add to the enticement, and yes DFO is open on the way into the airport to drop the wife off for some shopping to ensure you have a few hours to view the museum.
http://www.aarg.com.au/wheels.htmYou can do Point Cook and Moorabbin in one day, and I personally would push for Sunday at "Point Cook" 10am-12.30pm, "B24" 1.00 - 1.30pm include lunch as a drive through along the way?, 1 hour travel to Moorabbin, "Moorabbin" 2.30pm - 5pm with the wife in DFO for 2 hours and $100 spending money -smiles.
I'm not sure when you arrive but assuming your departing Friday after work?
You could be cheeky and take the family to the Titanic display at the Melbourne Museum on Saturday and you can view the Duigan Replica hanging from the ceiling, but that might be too greedy smiles.
But to be fair - take the family to Sovereign Hill in Ballarat on the Saturday to the open air gold museum -easily the best tourism experience in Victoria.
If you are driving down and leaving Friday afternoon see if you can come via Echuca for Friday night overnight stay and visit the Echuca Paddle Steamer port in the morning 8 - 11am, and then drive down into Ballarat 11 -1pm and go to Sovereign Hill on Saturday afternoon with an overnight stay for the "Blood on the Southern Cross", then off at 8am - 10am to get down to Point Cook for Sunday morning, Moorabbin/DFO in the afternoon. A great family trip -something for everyone.
That leaves a leisurely drive home on Monday back up the Hume, maybe a drop into Wang if your really cheeky!
regards
Mark Pilkington