Delivery of the first Airbus A321 passenger aircraft produced at the company’s Mobile, Alabama, plant is “several weeks” behind schedule due to problems with an un-named supplier.

Despite the problems, though, the France-headquartered aircraft maker said it expects to deliver it on time to JetBlue Airways in the second quarter of 2016.

“We had some jigs and tools issues with one of our contractors,” said Allan McArtor, chairman and CEO of the Airbus Group, referring to the large structures that hold parts in place, as well as the tools used to join parts.

“It was annoying. We’re angered, but not behind. We have enough flexibility to catch up,” he said, declining to name the company involved. “The contractor didn’t have very good program management. We had to hold their hand a little bit more.”

A second A321 for American Airlines will be delivered later in 2016. The A321 is the largest model in the Airbus A320 narrow-bodied family and is the primary competitor to rival Boeing’s iconic 737 series.

“If we look at the original master program, we’re a little bit behind schedule in certain parts of the project, but none of that is going to affect the actual delivery,” said Barry Eccleston, president of Airbus Americas Inc. “We still think we’ll make the delivery on the original schedule.”

Airbus began operations at the $600 million Alabama plant, its first in the U.S., in July 2015 and is slated to delivery four Airbus 321 jetliners a month starting in late 2017. Its operational template is a mirror image of the company’s assembly plants in Hamburg, Germany, and Tianjin, China.

Plans call for the Alabama facility to roll-out four aircraft per month by early 2018 for North America-based air carriers.