After rejecting an earlier contract, workers at Boeing supplier Spirit Aerosystems ratified a new contract, ending a strike at the Wichita, Kansas plant.

Striking workers at Spirit Aerosystems, a key Boeing supplier, will return to the factory after approving an enhanced four-year labor contract, the union said Thursday.

The International Association of Machinists (IAM) and Aerospace Workers, which launched a last week at the Wichita, Kansas plant after rejecting an earlier pact, announced the ratification in a .

The plant builds parts for the Boeing 737 MAX and 787, playing a major role in Boeing's supply chain for its two best-selling jets.

"We knew these negotiations were not going to be your typical set of talks," said IAM Local 839 Chief Negotiator Jason Baze.

"Our membership clearly said the original offer was unacceptable by rejecting it soundly. The committee returned to the table to address their concerns."

After the initial contract was overwhelmingly rejected, representatives of Spirit agreed to sweeten the package following talks with the union's team.

According to Spirit, highlights of the contract included: maintaining the ' existing ; increased pay and sign-on bonuses of $3,000 cash.

Striking workers will return to their jobsites on July 5.