In a reshuffle of its future fleet composition, Virgin Australia has ordered 23 new Boeing 737 MAX aircraft, which are scheduled to join the fleet between 2019 and 2021.
But it has delayed delivery of an undisclosed number of Boeing 737NG (New Generation) airliners until after 2016, the airline said today.
The rescheduling of the order book will still result in 31 B737-800 NGs joining the airline's fleet between 2013 and 2016.
By the end of this year, three of Virgin's seven remaining older B737-700s will be retired.
That leaves four 700s, which are to be refurbished with the airline's latest business and economy class interiors until they are retired by the end of next year.
The B737 Max aircraft are technologically more advanced than the NGs.
They are said to cut fuel consumption and consequent CO2 emissions by 13 per cent over comparable single-aisle aircraft.
"Virgin Australia is committed to maintaining a young and flexible fleet of modern aircraft. In the past year alone, we have reduced our average fleet age from 4.9 to 4.2 years," the airline's chief executive, John Borghetti, said.
The B737 MAX is powered by CFM International's Leap-1B engine, a joint venture between GE Aviation and France's Snecma group, a subsidiary of the Safran civil and military aerospace group.
It is a close relative of the Leap-1A engine to be fitted to Qantas's coming 78 Airbus A320Neos, which will first enter service with Jetstar.
The Leap engines feature long service intervals with innovations such as composite fan blades that resist bird strikes and air intakes that minimise sucking in runway grit into engine compressors.
Virgin Australia declined to reveal the commercial terms of the deal.