WICHITA, Kan. — Spirit AeroSystems and the union representing its engineers are asking a federal court to dismiss the union’s claims against the Wichita aircraft company over pension benefits.

The lawsuit by the Society of Professional Engineering Employees in Aerospace arose from Spirit’s 2005 purchase of Boeing’s commercial aircraft operations in Wichita.

The union is continuing its claims against Boeing. But in a joint motion filed Tuesday in federal court, the parties agree there’s insufficient evidence against Spirit AeroSystems to continue the union’s class-action lawsuit.

SPEEA says that after reviewing thousands of pages of documents and questioning 36 witnesses, it concluded that Spirit agreed only to offer future retiree health care benefits when it bought Boeing’s assets. The union could not find evidence Spirit violated its pension plans or bargaining agreements.