By Alex Mitchell in Sydney

An international airport decades in the making is set to finally open in October.

Western Sydney International Airport’s inaugural flight will take off on October 25, with its executives pledging to help ease demand on some of Australia’s busiest domestic routes.

Jetstar and Qantas tickets go on sale from Wednesday morning, with the budget carrier to run a combined 21 services a week to Melbourne, Brisbane and the Gold Coast.

Qantas will begin flying to and from the airport in March 2027.

The first flight out of Sydney’s second airport will be a Jetstar service to the Gold Coast at 11am on October 25.

WSI chief executive Simon Hickey said services announced on Wednesday morning were a starting point, with availability set to grow and provide customers more choice.

“Despite the ongoing global conflict that continues to challenge the industry, today’s domestic ticket launch is another vote of confidence in Western Sydney International Airport, and the opportunities this rapidly growing region presents for the future of air travel in greater Sydney,” he said.

Two international routes – Auckland and Changi – had previously been announced.

The airport, about 45km west of Sydney’s CBD, was finally approved in 2017 after decades of discussion around a second airport from the 1980s.

Prime Minister Anthony Albanese commissioned a joint study into how a second airport could be delivered when he was a minister in 2011.

“I said at the time, it wasn’t a matter of if Sydney needed a new airport, but when,” he said on Wednesday.

“I want to thank the tens of thousands of people who over the years planned, built and are now testing the airport and the surrounding infrastructure.”

The airport will operate 24 hours a day, in contrast to Sydney Airport, which is subject to a curfew from 11pm to 6am.

Vanessa Hudson, chief executive of Qantas – whose group also owns Jetstar – said it was a major moment for Australian aviation.

“Jetstar has an incredible history of growing new markets and being the first airline to launch will give one of the country’s fastest growing regions better access to low fares to some of our most popular destinations,” she said.