Delta will add up to 20 Embraer 190 and 20 new Boeing 737-900ER jets acquired through a new agreement with The Boeing Co.

The agreement is part of the airline’s continued strategy to improve its efficiency by adding additional 737-900ERs and upgauging its mainline fleet with the nearly 100-seat, twin-engine E190 jets while reducing the use of small regional aircraft.

The order announced today offered Delta more compelling economics over a previously cancelled order that also included Boeing-held E190s.

“Delta continues to look for opportunities to deploy larger aircraft, which bring customer experience enhancements and improved economics, across its fleet,” said Greg May, Delta’s Senior Vice President – Supply Chain Management. “This aircraft order is another example of Delta’s unique fleet strategy to deploy a mix of new and used aircraft, maintain low capital costs, and leverage significant capacity flexibility to produce superior returns for our shareholders.”

Expected to begin flying in early 2017, Embraer’s unique cabin design in the E190 includes two-by-two seating throughout the Main Cabin, one-by-two in First Class, and large overhead bins and oversized windows.

The additional Boeing 737-900ERs will bring the total in Delta’s fleet to 120 by 2019. The aircraft features large overhead bins and audio/video seatback entertainment with 20 seats in First Class, 21 seats in Delta Comfort+ and 139 seats in the Main Cabin.