Staff travel benefits vary from company to company, but with all(?) Australian airlines are on a standby basis only - that is you only travel if there are empty seats. It is relatively cheap (depending what you think an empty seat should be worth
) and works well if: you aren't travelling with dependents, you are flexible with your travel dates and you don't want to travel in peak times.
Generally if you think about what time you take your holidays and build a buffer in at the end to get home before going back to work it's pretty good. Have heard of several stories though of guys having to pay through the nose for a last minute ticket to get home when all the flights suddenly fill up.