AMSTERDAM (Reuters) - The head of Airbus told Reuters it is "not unlikely" that the European planemaker takes control of two U.S. and UK plants run by Spirit Aerosystems ( SPR ) if Boeing ( BA ) goes ahead with plans to buy one of the industry's key suppliers.

But Chief Executive Guillaume Faury said it was up to Boeing ( BA ) to fine-tune its intentions - having changed the status quo with a surprise plan to buy back its former unit - and Airbus would have a "word to say" about where the two factories ended up.

The fate of the plants and their combined 4,000 workers - in Kinston in North Carolina and Belfast, Northern Ireland - has been swept up in the latest crisis at Boeing ( BA ), which aims to buy its supplier to ease the fallout from a 737 MAX panel blowout.

"There are not many companies in the world that could be good owners for these activities," Faury said in an interview, when asked whether Airbus expected to have to acquire them.

"We make our wings so we could be a very legitimate owner of the activities in Belfast. And we do sections, so we could also be a very legitimate owner of the Kinston plant," he said.

"So that's part of the possibilities, and not an unlikely possibility. It's a not unlikely outcome, but it's not the only one."

Reuters reported last week that Boeing ( BA ), Spirit and Airbus were working directly or indirectly towards a potential "framework" that could lead to Spirit's break-up, with each planemaker taking some operations, but valuations were a hurdle.

The 500,000-square foot, robot-equipped Kinston composites plant makes panels for an upper fuselage section and a carbon-fibre spar, or beam, for each wing of the long-haul A350.

In Belfast, Spirit builds composite wings for the A220 in a plant previously owned by the plane's original designer, Canada's Bombardier. It relies on modern but costly technology that reduces the use of energy-guzzling pressurised ovens.

But the two state-of the-art Airbus-focused plants both lose money, raising questions how much if anything Airbus might be forced to pay to untangle Spirit for the sake of its arch-rival, industry sources say. Airbus bought the rest of the loss-making A220 programme from Bombardier in 2018 for a token U.S. dollar.

Faury did not discuss financial details or specific owners, but hinted Airbus was in no hurry to complete a deal.

"They (Boeing ( BA )) are in control," he said when asked about the timing of any agreement, adding that the current situation had arisen at Boeing's ( BA ) initiative.

"So we need to create a condition for having the discussion with Spirit ... because our relationship is with Spirit."

Airbus is not without leverage, he noted, including a traditional change-of-control clause. Airbus had to give approval when Spirit bought the Belfast plant from Bombardier in 2020.

"We have a word to say, and on top (of this) there are anti-trust laws. So we have room to discuss and that that's what will take place."

'NEW PARADIGM'

In remarks shedding new light on the speed at which the Jan. 5 blowout rippled through the industry, Faury suggested Airbus had been taken by surprise by Boeing's ( BA ) March 1 announcement that it would enter talks to reverse a 2005 spin-off.

"A few months earlier, maybe a few weeks earlier, my perception ... was that they were not interested in buying back Spirit," he said.

"That's a change of paradigm and we have to respond, but we need to know more about their intentions, the speed, how they want to do this," he said.

About a fifth of Spirit's revenues come from Airbus, with the vast majority of the rest coming from Boeing ( BA ).

Airbus has avoided being drawn publicly into Boeing's ( BA ) crisis, with Faury telling shareholders on Wednesday that it remains a tough competitor. But it is monitoring the impact of the turmoil, including a curb on 737 output that is vital to Spirit.

"Everything that happened to Boeing ( BA ) has indeed had an impact on Spirit and not necessarily a positive one, and therefore that's not good news for us because it's an important supplier."

Although aerospace firms occasionally supply each other, people familiar with the matter say Airbus is reluctant to see manufacturing of structural parts run by Boeing ( BA ) since it would give its rival an insight into production plans and pricing.

Data on the A350 "section 15" at Kinston is also considered so important that it triggered a row over whether it could be disclosed in an unrelated UK court dispute between Airbus and Qatar Airways last year, according to filings at the time.

Nor is crisis-ridden Boeing ( BA ) seen as interested in being distracted by the loss-making Airbus plants and likely future arguments over which programmes get resources, the people said.

Boeing ( BA ) had no immediate comment.

Led by Boeing ( BA ), aerospace firms have long experimented with outsourcing structural components to save costs. But the latest Boeing ( BA ) crisis has accelerated a rethink as planemakers prepare future designs and consider the risks of a globalised economy.

"It's core and it's single-sourced," Faury said when asked why aerostructures businesses like the two biggest Airbus-related plants at Spirit had fallen under the Airbus microscope.

(Additional reporting by Abhijith Ganapavaram; Editing by Tomasz Janowski)