Spirit AeroSystems engineers voted to ratify the company's contract, after twice rejecting previous offers.
Eighty-seven percent of the union members who voted approved the contract.
Two hundred sixty-six voted in favor while 40 voted against.
The Society of Professional Engineering Employees in Aerospace represents about 785 Wichita engineers.
Members voted on Wednesday and Thursday.
Union negotiators recommended acceptance of the offer, which they called improved from the previous ones.
"We're pleased with the results. I think there was a big turnaround in offer three," said Bob Brewer, SPEEA Midwest director.
"This was a long, tough negotiation. In the end, we found that landing spot."
Peter Perkins, a manufacturing engineer at Spirit, said, "It's not as good as we would have liked, but it's much better than the second offer."
Perkins said he thought most of the improvement was because the union increased its membership over the length of the negotiations.
Negotiations began June 9. Since talks began, union membership rose from about 29 percent to 58 percent of the represented employees, SPEEA said.
A federal mediator was called in for the latest round of talks. Last time, members also approved a strike authorization.
The three and a half year contract includes a guaranteed 3 percent bonus in 2010, guaranteed minimum increases in 2011 and 2012 and increases from market salary pools that are uncapped.
It also includes bonuses based on whether Spirit meets market targets and compensation for all hours of overtime worked, either in pay or comp time.
In addition, employees will have priority over contract labor during layoffs and shortened workweeks.
The cost of medical insurance premiums will rise from 10 percent to 15 percent for the life of the contract.