These days poor Jetstar seems to be consistently ranked as the worst reviewed, least on-time and generally most maligned airline in Australia, however, we fly them all the time and have literally never had a bad experience and Skytrax rated them as the best low-cost carrier in the Australia-Pacific region from 2011-2015, so who knows what to believe. Perhaps Australians would have more appreciation for how lucky they are if they took a few flights on some of Europe's low-cost carriers [editor's note: flying Ryanair is somewhere between the Third and Fifth Circles of Hell]. At the end of the day Jetstar will almost certainly be your cheapest option for domestic flights and flights to New Zealand from both Gold Coast and Brisbane airports.
