Airbus Group SE has delayed delivery plans for one of its newest long-range planes, adding to pressure on the European plane maker to meet commitments to airline customers.

TAP Portugal Chief Executive Fernando Pinto on Friday told The Wall Street Journal the carrier's first A330neo plane wouldn't arrive until March 2018. Airbus had initially promised the plane would be delivered around the end of next year.

Airbus is upgrading its A330 widebody with engines made exclusively by Rolls-Royce Holdings PLC. The enhancement, called the A330neo for new engine option, promises greater fuel efficiency and range. Airbus declined to comment.

For Toulouse, France-based Airbus, it is the latest in a string of setbacks which have hit the world's second-largest airplane maker after Boeing Co.

Airbus is struggling to meet a target to deliver more than 670 planes this year. The company has to deliver at least a record 94 planes this month to achieve that promise to shareholders. Plane deliveries are crucial to Airbus' cash flow.

Airliners have been slow to go out the door at Airbus because of supplier problems. Pratt & Whitney, the engine unit of United Technologies Corp., has fallen behind in building engines for some Airbus A320 single-aisle aircraft. Airbus has had some of the planes it had already built stuck on the ramp awaiting engines.

United Technologies Chief Executive officer Gregory J. Hayes this week told investors the company was making progress in catching up with building engines, but the job wasn't done. "There is still a handful of parts out there that we're chasing," he said.

Delays in obtaining plane seats and toilet doors also have set back delivery of A350 long-range planes. Airbus promised to hand over at least 50 of those this year. It had delivered only 34 in the first 11 months of the year.

The plane maker this year also said development of its largest twin-engine long-range plane, the A350-1000, had fallen behind plan. The plane, which first flew in November, won't be delivered until the second half of next year. Airbus previously had forecast a mid-2017 handover to the aircraft's first planned operator, Qatar Airways.

Airbus has sold 186 A330neo planes. TAP has ordered 14 of them. Mr. Pinto said the airline also planned to lease 6 more of the planes.