More than 200 airline pilots employed by a Qantas subsidiary have walked off the job for three days over a long-running pay dispute.
The industrial action from Wednesday to Friday will impact thousands of regional airline passengers and fly-in, fly-out workers.
The Network Aviation and QantasLink pilots in Western Australia will resume their strike on Monday for a further 24 hours.
Qantas Group previously said contingency plans had been made and most passengers would arrive at their destinations on the same day they were scheduled to.
"Customers whose flights are impacted on Wednesday have been contacted directly and offered fee-free date changes or refunds," a spokesman said.
"Those impacted on Thursday and Friday this week will be contacted."
It's the fourth time Network Aviation pilots have taken industrial action in recent months, amid accusations Qantas Group is refusing to negotiate and has taken previously agreed terms off the bargaining table.
Qantas has denied the Australian Federation of Air Pilots' allegations and says it did not walk away from talks and had been negotiating with the pilots' union for 18 months.
The airline on Wednesday said Network Aviation management had agreed to give the pilots another opportunity to vote on a proposed employment agreement on March 12.
Qantas said the offer that will be put to a vote is the same one that had union support in December but was voted down by the pilot group.
If the pilots vote to reject the pay offer the dispute will head to the Fair Work Commission for a hearing on March 14-15 to determine whether the parties have reached a stage where an outcome cannot be negotiated and arbitration is required.
Previous industrial action has forced Network Aviation to cancel and reschedule dozens of flights.
Network Aviation, which is owned by Qantas, is WA's premier charter company for the mining industry and operates hundreds of flights a week.