Qantas, Australia’s national airline, said on Monday that it had reached a deal with the country’s consumer watchdog to pay the equivalent of $79 million for selling thousands of tickets to flights that it had already canceled.

The airline said in a statement that the payments, totaling 120 million Australian dollars, would resolve a lawsuit that the Australian Competition and Consumer Commission filed against Qantas over the issue last year. The commission accused the airline of advertising and selling tickets for more than 8,000 canceled flights from May 2021 through July 2022.

The commission said Qantas had known that the flights would never take off, and that tickets remained available for an average of over two weeks after the flights were canceled — in some cases, for as long as 47 days.

Qantas said it expected to pay 20 million Australian dollars in compensation to more than 86,000 of its customers, as well as a fine of 100 million dollars, subject to court approval.

“We know many of our customers were affected by our failure to provide cancellation notifications in a timely manner, and we are sincerely sorry,” said the carrier’s chief executive, Vanessa Husdon.

“We have since updated our processes and are investing in new technology across the Qantas Group to ensure this doesn’t happen again,” she said.

Gina Cass-Gottlieb, the consumer watchdog’s chairwoman, said the agency was “pleased to have secured these admissions by Qantas that it misled its customers, and its agreement that a very significant penalty is required as a result of this conduct.”

The airline has had a rocky few years. While it bills itself as “the spirit of Australia,” its customers there have complained about unreliable flights and high ticket prices. The airline has also taken flack for giving large paychecks to its board and its previous chief executive, after what a court called its illegal layoffs of 1,700 baggage handlers.

In the airline’s statement Monday, Ms. Hudson said the resolution of the suit over the canceled flights “represents another important step forward as we work towards restoring confidence in the national carrier.”