If i were you i would catch a train the number is 131500 (i worked for cityrail at one stage) they will put you through to countrylink they go to byron and that way u can have a laugh with people u meet on there etc.Have a few drinks and have a good time.If your in the country why fly u might as well see the sights on the way.If leaving from Sydney the trains for Byron bay depart from Strathfield and Central stations i think a few times a day and the train you would get on would be called the XPT.Go by train but if your impatient catch a flight u will be there superfast probably less than 1 hour.