PARIS (Reuters) -Airbus struck a deal on Tuesday to sell up to 150 single-aisle aircraft to Vietnamese budget airline VietJet, as the European planemaker continues to rack up business at the Paris Airshow.

The companies said they had signed a memorandum of understanding for VietJet to buy 100 more A321neo planes, with the option to add up to a further 50 to the deal in future. The agreement confirmed an earlier Reuters story.

A deal for 150 A321neos could be worth around $9.4 billion, according to estimated prices provided by Cirium Ascend.

"These modern and efficient aircraft have been instrumental in VietJet's growth," VietJet Chairwoman Nguyen Thi Phuong Thao said in a statement released at a press conference attended by a delegation including several Western bankers.

"This landmark agreement represents a vital step in VietJet's growth strategy as a multi-national aviation group."

The planes will be delivered from 2030 onwards, and VietJet said it had financing in place for the deal.

European planemaker Airbus has announced a flurry of deals at the Paris Airshow, the world's biggest aviation trade fair that opened on Monday.

U.S. rival Boeing ( BA ) is expected to have a more subdued show as it focuses on the probe into last week's fatal crash of an Air India Boeing 787 and after it racked up huge deals during U.S. President Donald Trump's recent tour of the Middle East.

VietJet, the largest private airline in Vietnam, operates an all-Airbus fleet, apart from two Chinese-made regional jets. The airline has not to date taken delivery of any of the around 200 MAX planes it has ordered from Boeing ( BA ). Airbus is the main supplier of jets to Vietnam, accounting for 86% of the planes currently operated by Vietnamese airlines. However, the export-dependent Southeast Asian country is under pressure from Washington to buy more U.S. goods.

VietJet's latest deal comes only weeks after it ordered 20 A330neo wide-body airliners from Airbus.