On Monday, Southwest Airlines announced it is expanding its all-Boeing fleet and orders 100 more Boeing 737 MAX. The aircraft it purchases is Boeing 737 MAX 7 with options for 155 more.

The new purchase agreement takes Southwest’s order book to 200 Boeing 737-7s and 180 Boeing 737-8s, more than 30 of which have already been delivered. The new Boeing MAX 737 7s will replace Southwest’s aging fleet of Boeing 737-700s while providing better fuel efficiency.

This decision puts an end to the rumors that Southwest would prefer Airbus A220 to Boeing. The airline, indeed, did consider making a shift to Airbus, but, eventually, it chose to stick to Boeing 737. It has never purchased any other plane, not from the Boeing 737 family. For example, Delta Airlines and JetBlue Airways operate Airbus aircraft, which have similar characteristics and cost savings to Boeing 737 MAX.

“This cost-effective order book with Boeing allows the company to maintain the operational efficiencies of an all-Boeing 737 fleet to support its low-cost, point-to-point route network,” Southwest said in a statement.

 “Southwest Airlines has long been a leader and bellwether for the airline industry and this order is a big vote of confidence for commercial air travel. As vaccine distribution continues to pick-up, people are returning to the skies and fueling hopes for a full recovery and renewed growth across our industry,” said Stan Deal, president and CEO of Boeing Commercial Airplanes.