VietJetAir on Tuesday placed a firm order for 63 Airbus A320 jets with a list price of $6.4 billion in a massive expansion drive by the privately owned budget carrier founded only in 2011. The deal, signed on the opening day of the Singapore Airshow, also covers rights to acquire or lease additional A320s potentially boosting VietJetAir's current fleet of 11 A320s tenfold. "The A320 has proven to be extremely efficient in service with VietJetAir and is a favourite with our passengers," the firm's managing director Luu Duc Khanh said in a press statement issued by Airbus. The low-cost carrier currently has a fleet of 11 leased A320s plying domestic routes as well as services to Bangkok, Seoul and Kunming in China. "We look forward to developing our business across the Asia Pacific region," Luu said, adding that Airbus would be a "strategic partner" in its regional expansion. Fabrice Bregier, the president and chief executive of Airbus, said the order "reinforces the A320 family's position as the preferred choice in the single aisle market, both for full service and low cost carriers." "We look forward to working with VietJetAir as it brings ever more affordable air travel to the fast growing South East Asian market," he said in the statement. There have been more than 10,100 orders and 5,900 deliveries of the A320s to over 300 customers and operators, making it the world's best-selling single-aisle aircraft, according to Airbus.