Chart of the Week #4: Did Rex really have a better on time performance?

This week’s “chart of the week” follows some recent events and takes another look at Rex following their decision to enter voluntary administration late last month. Specifically, it considers Rex’s on time performance, something they regularly exploited for marketing purposes.

Australia has transparent punctuality and reliability data for domestic airlines. The Bureau of Infrastructure and Transport Research Economics (BITRE) published monthly data by route and airline. BITRE defines a flight as cancelled if it is cancelled or rescheduled less than 7 days prior to its scheduled departure time. An on time arrival is defined as arriving at the gate within 15 minutes of the scheduled arrival time. A weakness of these data are that it doesn’t allow any inference to be draw on the severity the delay: a 16 minute delay is as good as 16 hours!

So back to the question at hand: was Rex more reliable than other carriers? The answer is an unequivocal YES! Let’s delve in in a little more detail.

We consider the cancellation rate of Rex and all other airlines combined on overlapping routes, specifically looking at the “golden triangle” (i.e. routes between Brisbane, Melbourne and Sydney) and all Rex’s jet routes (i.e. routes flown by their B737 service).

Considering cancellation rates, Rex has significantly lower cancellation rates than all other carriers combined on overlapping routes over the last year. Other carriers include Jetstar, Qantas (including Qantas Link) and Virgin Australia (including Virgin Australia Regional). Notably, while cancellation rates of other carriers declined from the start of 2024, while Rex’s performance weakened with a poor February and cancellation rates increasing in May and June.

Considering on time arrival rates, Rex has significantly higher on time arrival rates than all other carriers combined on overlapping routes over the last year. Notably, on time arrival rates appear to follow systematic seasonal variations as indicated by a strong correlation in downward and upward trends between Rex and other carriers. For example, on time performance weakened for both Rex and other carriers in the summer months and recovered in the new year. This is likely due to increased airspace and airport congestion during the peak summer months combined with weather disruptions due to summer thunderstorm activity. What this highlights is that Rex suffered from the same exogenous operational challenges as all other airlines.

So what was Rex doing differently? We don’t think they were doing too much differently actually. There are several hypotheses:

1. Smaller airline: simply put, being smaller meant it was easier to manage. Aircraft and crew scheduling is less complicated.

2. Fewer network connections: having fewer network connections to/from other flights (own or partner) means less likely to tactically delay flights.

3. Lower aircraft utilisation: Rex’s smaller fleet size meant smaller economies of scale meaning lower aircraft utilisation at slot constrained airports. This may have also contributed to poor financial performance and there is an argument to be made that it’s better on time performance was a (small) contributor to its downfall.

Rex’s superior operational performance shouldn’t be written off. Ultimately, a greater proportion of their passengers got to their destinations on time, but it’s not a fait accompli that it would have maintained this had it achieved a larger scale.

And just in case you missed last week’s “chart of the week” you can find it here: