Originally Posted by number_6

QF has mostly stopped running tag-ends of international flights (with international service level!) but JQ runs several. Also UA SYD-MEL-SYD is "international" with international rules (restricted liquids). At some airports the int and domestic terminals are far apart so it matters quite a bit which it is. A quaint legacy of the time when Australian airlines were split between domestic and international and never the twain shall meet. A bit like PanAm I suppose.