Boeing and WestJet announced today that they have completed an order for 65 737 MAX airplanes, fulfilling the carrier’s letter of intent to purchase the airplanes announced on Aug. 29.

The order, valued at $6.3 billion at list prices, consists of 40 737 MAX 8s and 25 737 MAX 7s. The airplanes are a key component of the Calgary-based airline’s fleet renewal initiative.

“We are pleased to announce the finalization of the MAX purchase agreement and look forward to being among the first North American airlines to fly the 737 MAX in 2017,” said WestJet President and CEO Gregg Saretsky in a press release. “The increased fuel efficiency and enhanced in-cabin amenities provided by the Boeing 737 MAX will contribute to both lower operating costs and a remarkable in-flight guest experience which is supportive of our low-cost business model and combined with our lease renewal options, maintains our fleet plan flexibility going forward.”

The 737 MAX brings the most advanced engine technologies to the world’s best-selling airplane, building on the strengths of today’s Next-Generation 737. The 737 MAX incorporates the latest-technology CFM International LEAP-1B engines to deliver the highest efficiency, reliability and passenger comfort in the single-aisle market.

Airlines operating the 737 MAX will see a 13 percent fuel-use improvement over today’s most fuel-efficient single-aisle airplanes, according to Boeing.

“The 737 MAX is an excellent complement to the WestJet fleet and its low-cost business model,” said Brad McMullen, vice president of North America Sales, Boeing Commercial Airplanes. “The airplane’s efficiency, reliability and passenger amenities will enable WestJet to continue to provide its customers high-quality service at a low cost.”

The WestJet order continues the momentum of the 737 MAX in the marketplace. The order brings the total number of 737 MAX orders to date to 1,567 airplanes.