Accessing Melbourne Airport by public transport from Melbourne’s west is a pain. It really should not be difficult since the airport is actually in Melbourne’s (north-) west, but there is no easy bus from western transport hubs, not even from Sunshine which services a Metro rail corridor and two (potentially three) V/Line country rail routes.
For decades now the community has been calling for a train to the airport but, probably due to a whole range of factors, it is yet to be built. However, if it were to be built it would most likely run via Sunshine as seen in Public Transport Victoria’s Network Development Plan.
There is no reason why the potential rail route could not be serviced right now by a direct and frequent bus, at least one every 20 minutes. It could run directly north from Sunshine Station using McIntyre Road, the Western Ring Road and the new Airport Drive extension. The route is about 16 kilometres long according to Google Maps and would take 20 to 30 minutes depending on traffic and passenger loading.
The route need not be express and could also service locals in Sunshine North and airport workers stationed near Airport and Melrose drives. It would also work best as a myki ticketed service so users would not be discouraged by a requirement for multiple tickets transferring between train and bus.
The bus would provide reasonably easy access to the Airport from Bendigo, Castlemaine, Kyneton, Woodend and Gisborne in the state’s north-west, but only if trains on the Bendigo Line stop at Sunshine which none currently do. The bus would also provide access from Ballarat, Ballan, Bacchus Marsh and Melton heading directly west, as well as, and probably most usefully, the suburbs of Geelong as well as Lara and Tarniet in the south-west.
Everyone travelling from these places would otherwise need to travel all the way into Melbourne and use the costly Sky Bus service, use often inconvenient once-a-day airport shuttle busses from their local town or get a friend or family member to drive them to the airport.
If you think this is a good idea let your member of state parliament know and contact PTV, too.
augustusbrown 
Two points. For the Bendigo line and for Sunbury at least as far in as Keilor Plains, the 30 minute duration 60 minutes between 6 am and 8 pm weekday frequency, but only two services per day on weekends, 479 between Sunbury and the Airport offers at least as good a path as we could ever get via Sunshine, with only the frequency to be adjusted. It is also a better prequel to Rail Futures’ and others’ proposal to divert the Bendigo line near Wildwood to service the Airport by V/Line and giving Bendigo full RRL separation.
The other is the Anderson-Macintyre-Ballarat Roads intersection which is arguably the least reliable in Melbourne despite there being a VicRoads office around the corner. One simple and obvious fix has been on indefinite hold because of a notional reservation for extending Foundry Road via the vacated Sunshine Bowl site to St Albans Road outside Albion Station. It would be a lot simpler to widen Anderson Road north bound to four car plus existing one bus lanes and fix the lights cycle so the left most lane could feed St Albans Road through most of the cycle and the second left could feed Ballarat Road through more than half. Until that is fixed one way or the other, it isn’t the kind of route to rely on to catch a plane.