AirAsia has placed an order for 150 Airbus A220-300 aircraft, in the largest single purchase yet for the type. The deal makes the budget airline the biggest customer for the A220 programme, overtaking Delta Air Lines.

The order is valued at about $15bn, according to the information provided. AirAsia also becomes the first customer for a new A220-300 configuration designed for 160 passengers.

The announcement confirms the end of speculation over the carrier’s fleet plans. It gives Airbus a major boost for its smallest jet family and strengthens AirAsia’s push to expand its network with a more efficient narrowbody aircraft.

The A220 has become an important aircraft for airlines looking for lower operating costs on short and medium-haul routes. The type competes in a segment where fuel efficiency, range and cabin comfort can influence airline buying decisions.

For AirAsia, the order marks a significant step as it continues to rebuild and grow after years of industry disruption. The carrier did not disclose a delivery timetable in the material provided.

The A220-300 is designed to carry between 100 and 160 passengers, depending on cabin layout, and is aimed at routes that do not require larger jets. AirAsia’s version at 160 seats puts it at the upper end of the model’s typical seating range.

Airbus has been steadily building demand for the A220 from airlines around the world. With this order, AirAsia becomes a headline customer for the programme and gives the manufacturer one of its biggest single airline commitments in recent years.