Boeing Co and the union that represents its 23,000 engineers tentatively agreed to resume labor talks on Tuesday, after their negotiations on a new contract ended abruptly on Thursday.
But tension rose as the two sides sparred over efforts to engage a federal mediator to help them reach a new labor contract.
Boeing said late on Friday that the union had declined its offer to attend meetings with the Federal Mediation and Conciliation Service in Washington, D.C., on Monday.
The Society of Professional Engineering Employees in Aerospace (SPEEA) said it had contacted the mediator before Boeing did, and was waiting for Boeing to confirm dates for meetings next week that it had arranged.
"We told SPEEA we'd like to start meeting with a federal mediator Tuesday in Seattle," Boeing spokesman Doug Alder said. "We are still working out the details with SPEEA and the mediator."
SPEEA's chief said the union was willing to meet, too, and with a different mediator if necessary.
"I've responded that we have a mediator assigned to us ... but if Boeing is dissatisfied with that mediator, they need to take that up with FMCS not us," Ray Goforth, SPEEA executive director, said.
"We also don't see the need to meet in a hotel. I offered to meet on Boeing property if that would make them comfortable."
The two sides have been negotiating since April to replace a labor contract that expired November 25.
The union has balked at a Boeing contract that it says would cut the growth rate of compensation of professional and technical employees. Boeing says its latest offer is much improved over its initial proposal and reflects a tough competitive environment.
Talks broke down Thursday after Boeing said it wanted a mediator.
The dispute comes as Boeing looks to speed up jet production from 52 a month to about 60 a month by the end of next year. A walkout by the union could stop production.
Peter Arment, an analyst with Sterne, Agee & Leach, expressed hope that the dispute would be resolved with mediation. He noted strikes by SPEEA were rare, with the last one occurring in 2000.
"There's still time for this to be resolved long before it would affect Boeing's commercial aircraft production," Arment said.
Shares of Boeing edged down 3 cents to $74.09 in Friday trading.
(Reporting by Alwyn Scott in New York and Karen Jacobs in Atlanta; Editing by Lisa Von Ahn and Eric Walsh)