CHICAGO—Delta Air Lines Inc. is ordering 100 737 Max 10 airplanes, the largest of the line produced by Boeing, potentially giving the manufacturer additional momentum after a troubled rollout of its most advanced aircraft.

Delta has an option to purchase 30 more of the aircraft as the airline looks to keep up with surging travel demand.

Boeing has struggled to keep up with its European rival Airbus after a pair of 737 Max aircraft crashed in a short span of time, killing 346 passengers and crew members.

Airlines are aggressively trying to reduce costs, and the 737 Max can help them do that. Delta Air Lines said that the airplanes, which can seat up to 230 people, will reduce fuel consumption and emissions by 20 to 30 percent compared with the planes they will replace.

However, the Max 10 has not been certified by federal regulators. Boeing is rushing to get that approval before a year-end deadline, when new standards enacted after the crashes would require that the planes have a cockpit-alert system that warns pilots about some malfunctions on the plane.