Qantas has recorded a 13 per cent fall in its post-tax profit to $873 million in the six months to December 2023, largely driven by lower airfares as its capacity returns to normal after the COVID-19 pandemic.

The airline's preferred profit measure of underlying profit before tax also fell by 13 per cent to $1.25 billion in the six months to December 2023.

It follows the airline reporting an annual profit of $1.7 billion last financial year — its first since before the COVID-19 pandemic grounded the aviation industry.

Its half-yearly results are the first delivered under chief executive Vanessa Hudson, who replaced Alan Joyce in September after he fast-tracked his planned exit from the company after a series of scandals plagued the airline.

Ms Hudson said the results follow months of work on its services after "loud and clear" feedback, and the airline has seen a significant improvement in customer satisfaction.

"There's a lot of work happening to lift our service levels and the early signs are really positive," she said in a statement.

"Our customer satisfaction scores have bounced back strongly since December, and we have more service and product improvements in the pipeline.

Ms Hudson said the airline has also seen fewer cancellations and delays, and the return of international travel has benefited its costs.

"The journey we're on will take time, but the spirit [our people] are bringing is fantastic and it's made us optimistic about what we can achieve together," she said.

In its results, Qantas reported carrying more than 26 million passengers between July 1 and December 31 last year — an increase of 3.3 million passengers compared to the same time a year ago.

Jetstar, its lower cost airline, saw an 84 per cent increase to its pre-tax profit of $325 million, up from $177 million compared to last year's half-year results.

Its domestic network contributed $175 million to Jetstar's overall pre-tax profit, with its international network adding $150 million.

However, both Qantas' domestic and international offerings saw a drop in profit: its domestic airline profit before tax fell from $785 million to $641 million, while its international flight business dropped by 31 per cent to a pre-tax profit of $322 million.

Ms Hudson told an investor briefing that Qantas is focused on investing in Jetstar as a result of its increase in demand as travellers seek out lower airfares.

As Qantas' capacity returns to pre-COVID levels, the airline expects it will be managing higher industry costs in the second half of the financial year.

The company said rising fuel costs are also having an impact on the airline, and expects fuel costs will total $5.4 billion in the 2024 financial year.

Qantas will not pay a dividend to shareholders, but instead will return money to investors through its share buy-back program, worth up to $400 million.

Despite its multi-million-dollar profit, Qantas' earnings will come under pressure as the airline plans to spend $3 billion by the end of the financial year, with the bulk put towards renewing its fleet.

As part of its long-term performance, Qantas is investing in new Airbus A220 jet aircraft to replace its fleet of Boeing 717s.

The airline has also ordered another eight Airbus A321XLRs for its Qantas domestic fleet, in addition to its previous order of 20 aircraft, to steadily replace its fleet of Boeing 737 aircraft beginning in early 2025.

Qantas had initially forecasted the first planes would arrive by the end of 2023, but manufacturer Airbus has twice delayed the aircraft's entry-into-service, which is now expected between July and September this year.

Qantas has also committed to employing more staff at its call centres to improve customer wait times, and upgrading wi-fi speeds on all its international flights later this year.

Qantas' half-yearly earnings results come as the airline faces an uphill battle to restore its reputation after a series of scandals saw its former boss depart two months ahead of schedule.

In May last year, Qantas named Ms Hudson — then its chief financial officer — as Alan Joyce's replacement, who was retiring from the company in November after 15 years.

But by August, the airline was hit with a class action lawsuit, alleging it had breached consumer laws by failing to issue refunds for cancelled flights in 2020 and only offering flight credits with "strict conditions".

(A month earlier, Qantas had launched a campaign to encourage customers to use their flight credits before they expired at the end of 2023.)

Later that same week, Qantas announced its annual profit of $1.7 billion — a record turnaround from an airline that saw losses of $4.5 billion during the pandemic, despite receiving $2.7 billion in federal government assistance, including $855 in the JobKeeper wage subsidy.

Meanwhile, Qantas was facing questions about whether it had any influence in a decision made by the federal government to reject additional flight requests made by Qatar Airways.

A week later, the Australian Competition and Consumer Commission (ACCC) launched legal action against the airline, alleging it had sold more than 8,000 tickets for "ghost flights" — flights that had already been cancelled in 2022.

ACCC chair Gina Cass-Gottlieb told the ABC that the record penalty for a breach of consumer law was $125 million, with a spokesperson from the watchdog later clarifying the fine could potentially be hundreds of millions of dollars.

Qantas has denied the allegations, and filed its defence with the Federal Court in November stating customers don't buy tickets, but instead a "bundle of rights".

That same day, Qantas removed the expiry date on $570 million worth of flight credits owed to customers, and offered cash refunds.