Qantas and Jetstar will be the first airlines to fly domestically from Sydney's new $5.3 billion airport in the city's west.

The construction of the Western Sydney Airport has now reached the halfway mark and is on track to be open in late 2026. 

The Australian airlines are the first to sign a commercial agreement with the airport. 

The deal involves basing five Qantas and 10 Jetstar aircraft at the Badgerys Creek site, within its first year of operating. 

The planes will fly domestic routes to destinations including Melbourne, Brisbane, and the Gold Coast. 

It is estimated the aircraft will move 4 million passengers on more than 25,000 flights each year, and create 700 jobs. 

Qantas chief executive Alan Joyce said the new airport would be the most technologically advanced and efficient in Australia. 

"I have absolutely no doubt it will be the biggest airport on the Qantas network one day," Mr Joyce said. 

"It'll have shorter block times, shorter taxi times, [and] allows us to turn around aircraft faster."

Mr Joyce said talks are ongoing with the airport about operating international and freight routes. 

The Western Sydney Airport will be the first in New South Wales to operate with no curfew, 24 hours a day. 

It will eventually move 80 million people throughout Australia and overseas each year. 

Prime Minister Anthony Albanese described the airport as a "transformational project for Western Sydney", which has already brought in $400 million to the local economy and created more than 4,000 jobs. 

"This is about jobs and economic activity and changing the focus of Sydney," Mr Albanese said. 

The airport's chief executive Simon Hickey said it was designed for growth.

"Over the decades ahead it'll actually become the same scale and size of JFK and Dubai."