During the initial 3 hours of yesterday's flight delay I parked next to a power point with laptop & 3G USB stick and dug around for on time performance statistics to see if any of the Aussie airlines are better or worse than the others.
The Bureau of Infrastructure, Transport, and Regional Economics collates on time performance statistics for the Australian domestic market. As with all statistics the correctness of the data is a little questionable (Qantas and JetStar submit flight stats via ACARS whilst the others submit their own mix of hand-recorded data) but its all we've got.
The definitions are as follows:
A flight departure/arrival is counted as "on time" if it departs the gate within 15 minutes of the scheduled departure/arrival time shown in the carriers' schedule. Neither diverted nor cancelled flights count as on time.
A flight is regarded as a cancellation if it is cancelled or rescheduled less than 7 days prior to its scheduled departure time.
The cynic in me would logically conclude that once a flight is delayed beyond its 15 minute buffer the airline should totally burn the flight to maintain the on time performance of same sector flights since the metric does not account for total time delay, just whether the flight is delayed or not.
Eyeballing the (PDF warning) August & September 2009 stats it isn't immediately clear that any of the airlines are better or worse for the Sydney<->Melbourne route. Flight arrival delays vary between 72.9% and 83.3%, and cancellations reach as high as 5.8%. Qantas and Virgin Blue appear to be the best performers on this sector though it should be noted that Jetstar is not fairly represented since they fly mostly into Avalon (which isn't anywhere near Melbourne so I guess it is fair in that respect :).
At an aggregate level (i.e. across all sectors) Qantas and Virgin Blue appear to be the picks for best overall on time arrival performance. Virgin Blue has historically had a poorer cancellation record but as the difference is just 1% I would caution reading too much into the aggregate figures since performance can vary quite greatly by sector.
In relation to my experience yesterday with Tiger Airways I think one important factor is the number of flights each airline is running on each sector. Qantas & Virgin Blue are each running over 800 flights in each direction on the Sydney<->Melbourne route, compared to around 120 flights for Tiger Airways. Assuming they all run similar loads it would seem that Qantas & Virgin Blue would more likely have capacity to absorb passenger loads caused by a mechanical failure or other incident.
Overall it seems to me that as a budget holidayer doing Sydney<->Melbourne I'd be best off trying to pick up a special on Qantas or Virgin Blue. Looking 3 Saturdays out from now there are sub-$100 tickets on both. I'd only consider Tiger or Jetstar if their tickets were under $50 and their flight times were better suited to my schedule.