There were a record number of flight cancellations in June as Melbourne's fourth lockdown and Sydney's burgeoning Delta variant outbreak hit interstate travel.
Figures from the Bureau of Infrastructure and Transport Research Economics showed 24.5 per cent of all domestic flights in June were cancelled, the highest number since reporting began in November 2003.
This compared with just 2.5 per cent of flights cancelled in June 2020, albeit with a much lower number of scheduled flights. The long-term average for flights cancelled is just 1.8 per cent.
Jetstar had the highest number of cancellations, with almost 40 per cent of flights cancelled, followed by Virgin Australia (31 per cent), Qantas (29.1 per cent), QantasLink (13.5 per cent), Regional Express (11.1 per cent) and Virgin Australia Regional Airlines (1.3 per cent).
Melbourne's fourth lockdown was the main culprit for the high number of cancellations, with Western Australia's tendency to close borders quickly making flights between Melbourne and Perth the worst affected. Almost three-quarters of all flights were cancelled on the route.
Almost 72 per cent of all flights on the Sydney-Melbourne route were cancelled, a route that is typically one of the busiest in the world.
Despite the high number of cancellations, the on-time performance of the flights that did depart was above the long-term average, at 84 per cent. Virgin Australia had the best performance for on-time arrivals at 86 per cent, while Qantas had the best on-time departures at 87 per cent.
July's cancellation rates may be lower as airlines have significantly cut the number of scheduled departures in response to the virus outbreak in Sydney.
Qantas chief executive Alan Joyce told the Sydney Morning Herald and The Age this week that the airline may have to stand down staff if lockdowns continued.
Qantas has reduced its flights to less than 40 per cent of pre-COVID levels as a result of the lockdowns in NSW, Victoria and South Australia.
A spokesperson for Virgin Australia said the airline's domestic flights had been reduced by 50 per cent due to the ongoing lockdowns and border closures. Rex, which has been aiming to compete with the two larger airlines on routes between major cities, has cut all its major metro routes and greatly reduced regional flights.
Australian airlines are currently offering some flexibility for passengers booking, typically in the form of fee-free changes or flight credits if border closures disrupt plans. Refunds are also available depending on the airline and circumstances.