From what I can gather if you are employed as a casual you arent gaurenteed any hours [unlikly I would think though but possible] But I suppose you would have to be prepared for the quiet months, down turn in avaition, Jetstar growing etc etc etc.
The big issue for me though would be...how do financial institues, banks etc feel about lending you money for home, car loans etc when you have no gaurenteed income??
I am presuming also there is no staff travel benifits as you arent employed by QF??