Lessor BOC Aviation is ordering another five Airbus A321s, to be delivered in 2017.

All five are being leased to an Asian carrier, although the lessor has not identified the customer. An engine selection has yet to be disclosed.

BOC Aviation says the order is a response to the “market trend and appetite” for larger-capacity single-aisle aircraft.

Airbus has confirmed the order by the Singapore-based leasing company.

BOC Aviation’s agreement follows an order for 30 A320-family jets originally placed in January this year, before Airbus shifted it to the 2015 order total.

That agreement included 15 A321s, says the airframer, eight of which were the re-engined A321neo.

Airbus chief operating officer for customers John Leahy says the deal confirms a pattern of “upsizing” by customers.

BOC Aviation is one of Airbus’s largest customers, with cumulative orders for some 300 A320-family jets as well as a dozen A330s.