Jetstar has cancelled more than 50 flights as union staff at the low-budget airline continue rolling strikes across the country.
The Australian Federation of Air Pilots says the union's Jetstar pilots will undertake four-hour work stoppages on Sunday.
Jetstar has cancelled 54 flights in advance to minimise disruption to travellers, according to a travel alert issued by the company.
A similar strike on Saturday caused the proactive cancellation of more than 40 flights.
The pilots' action comes after baggage handlers and ground staff stopped work on Friday at Sydney Airport, Melbourne's Tullamarine and Avalon airports, and in Brisbane, Cairns and Adelaide.
Staff are striking in protest over pay and health and safety concerns they say the airline has not addressed.
Jetstar says the strikes are "unjustifiable" and "cynically timed to hurt travellers at the busiest time of the year".
Workers who walked off the job on Friday have pledged to do it again next Thursday should their demands not be met.
The company says customers travelling from December 13 to December 20 can request a full refund prior to flying.
Australian Associated Press