Airbus may end up owning some assets of Spirit AeroSystems in Scotland and Malaysia if the transatlantic supplier is unable to find a buyer for them, a filing from the aerostructures company showed on Monday.

The European planemaker has agreed to take over core activities at four of the supplier's plants in the United States, Northern Ireland, France and Morocco, while rival Boeing would take a few others.

Spirit said on Monday it planned to sell operations in Prestwick, Scotland and in Subang, Malaysia that support Airbus programs and those in Belfast that do not support the programs.

However, Spirit's term sheet with Airbus - named "Project Sparrow" - leaves the door open for the planemaker to own parts of two plants that were not a part of the deal announced on Monday.

Airbus and Spirit shall cooperate to "implement an alternative arrangement pursuant to which the Subang Assets and the associated liabilities shall be allocated and transferred to Spirit and Airbus" if the assets are not bought by a third party before mid-2025, the filing showed.

The Subang plant makes wing fixed leading edge and wing movable leading edge for Boeing's 787 Dreamliner, according to Spirit's website.

Its Prestwick plant, which makes wing parts for Airbus A320, could be classified under "transferred business" if a buyer could not be found, the filing said.

Airbus Kinston, the Belfast Airbus business, the A220 Pylon business and the Morocco business that the planemaker is buying are already part of such a classification.

Since Spirit's Airbus-related activities have been losing money, Airbus said it would receive $559 million in compensation from Spirit, depending on the final outlines of the deal, while it would pay the supplier a symbolic $1 for the assets.

"We are evaluating options for assets that may not be acquired by Boeing or Airbus. The ultimate owner for those operations as a result of this process may be Boeing, Airbus or a different owner," Spirit Aero senior vice president of Airbus and Regional/Business Jets Programs said in a letter.

Spirit owes Airbus $122.1 million under a loan arrangement, the filing showed.

Separately, Spirit said it has set up a cash-based program of $50 million to promote employee retention and to incentivize efforts to complete the merger.

 - Reuters