AirAsia X, the long-haul affiliate of Asia’s largest low-cost airline, has placed a firm order with Airbus for 55 A330neo aircraft.

This is the largest single order to date for the best-selling A330 Family and reaffirms AirAsia X’s position as the biggest A330 airline customer worldwide, having now ordered a total of 91 aircraft, it said in a statement here today.

The announcement covers the firming up of a memorandum of understanding for 50 A330neo signed during the Farnborough Air Show in July 2014, plus an additional five aircraft.

Deliveries of the newly-ordered aircraft will begin in 2018, it said.

"This latest deal with Airbus will enable AirAsia X to consolidate its growth rate in 2015-2017 before ramping up deliveries from 2018 onwards," said Tan Sri Tony Fernandes, Co-Founder and Director of AirAsia X.

The A330 has proven itself to be exactly the right aircraft for the group's business model, combining low operating costs, long range flying capability and high levels of comfort, he said.

"We are extremely excited about the even greater levels of efficiency that will come with the A330neo, which will play a key role in enabling AirAsia X to maintain its position as the long-haul low-cost leader," he added.