Delta Air Lines has agreed with Airbus SE to place an expanded A321-200 order for 30 firm additional aircraft and to defer 10 of the airline’s 25 A350-900 aircraft deliveries set for 2019-2020 by two to three years with additional delivery flexibility.

Delta’s delivery schedule for its first A350-900 aircraft remains in place and the airline plans to operate its first A350 revenue flight in the fourth quarter, featuring the Delta One Suite and Premium Select cabin. Delta expects to take delivery of five A350s in 2017.

“These agreements better align our widebody and narrowbody order books with our fleet replacement needs,” said Gil West, Delta’s Senior Executive Vice President and Chief Operating Officer. “We appreciate the partnership of Airbus, Rolls-Royce and GE Aviation as we exercise what’s best for our business, our employees and our customers.”

Delta currently operates 19 A321s and this expansion will bring the total firm delivery aircraft from 82 to 112 by 2021. The A321 aircraft will primarily be deployed on U.S. domestic routes as older domestic-gauge aircraft retire during the next several years.