If you breast feed, make sure your little one is well latched on, if you don't, ensure a bottle is well and truly at the ready. Try to travel during your baby's natural sleep time. Keep it short. It is unrealistic to expect a dream passage to Australia with a wriggly baby on your lap. Take warm clothing for flights.
Aeroplanes have Arctic air conditioning.
If you are travelling by car, plan plenty of breaks. Pack them their own little picnic box with a few favourite treats to munch. Don't take their beloved cuddly. There is no other sure-fire way to ruin your holiday than losing their most precious companion. If all else fails, sing.