SINGAPORE - European aviation giant Airbus said Thursday that Vietnamese airline Vietjet Air has agreed to buy 20 of its A330-900 planes.

Vietjet signed a memorandum of understanding with Airbus for the widebody aircraft, which will replace its current fleet of leased A330-300 planes, Airbus said in a statement.

"We are excited to work with Vietjet on the next phase of the carrier's expansion," said Christian Scherer, chief executive of Airbus's commercial aircraft business.

When finalised, the order will be Vietjet's largest-ever widebody purchase, the airline said.

Benoit de Saint-Exupery, executive vice president of sales at Airbus's commercial aircraft business, described the deal as a "commitment to purchase" by Vietjet during a briefing at the Singapore Airshow.

Exupery said the firm expects the deal to be finalised "in the next few weeks", and the first delivery will be in 2026.

Airbus did not provide a value for the deal. At list prices, the Vietjet order would be worth $5.9 billion, but customers usually get a discount when making bulk aircraft orders.

Budget airline Vietjet operates a fleet of 110 aircraft on about 30 international routes.

The new aircraft will operate on the carrier's growing long-range network, as well as on high-capacity regional services.

They will replace the carrier's current fleet of leased A330-300s, as well as provide for network expansion.

"The new A330neo aircraft is a strategic addition to modernize Vietjet's fleet comprehensively," Vietjet chief executive Dinh Viet Phuong said in a statement.

"The introduction of the new-generation A330neo into Vietjet's fleet will play a crucial role in the airline's sustainable development strategy with ESG goals, aiming to achieve net-zero emissions by 2050," he said.

Vietnamese airlines have been eagerly growing fleets to serve burgeoning passenger numbers, where domestic travel has soared in recent years and international air travel is on the rise.

Vietjet stormed onto Vietnam's airline sector in 2011 when much of the market was dominated by the national carrier Vietnam Airlines.

The country's first budget carrier, owned by Vietnam's only female billionaire Nguyen Thi Phuong Thao, initially raised eyebrows with its racy marketing campaigns featuring nearly naked models and by staffing inaugural flights with air hostesses wearing bikinis.

The government said the airline's share of domestic passenger travel was around 40 percent in 2022, the latest year figures are available.