If a simple majority approve the offer, it would end the more than seven-week work stoppage that has halted most of the struggling company's airplane production, another curve ball in what executives had once cast as Boeing's turnaround year.
The proposal includes 38% raises over four years, up from the 35% increase Boeing proposed and workers rejected late last month, extending the strike. The deal that kicked off the strike in September had 25% raises, while the union had originally pushed for pay increases of about 40%.
Boeing said machinist pay will average $119,309 at the end of this contract proposal.
Workers have complained about the skyrocketing cost of living in the Seattle area, where most of Boeing's aircraft are produced.
But the union, upon unveiling the proposal last Wednesday, warned this deal might be as good as workers are going to get.
"In every negotiation and strike, there is a point where we have extracted everything that we can in bargaining and by withholding our labor," the International Association of Machinists and Aerospace Workers District 751 said in a statement. "We are at that point now and risk a regressive or lesser offer in the future."
On Saturday, the union told workers that it is "truly the time to lock in these gains and work to build more in future negotiations. You can confidently declare victory, vote yes for this agreement, and build on this for generations to come."
Boeing CEO Kelly Ortberg, who took the reins in August, also urged workers to come back to work.
"I know the strike has been difficult for you as well as for our customers, suppliers, communities and all who work at Boeing," he said in a staff note on Friday. "It's time we all come back together and focus on rebuilding the business and delivering the world's best airplanes. There are a lot of people depending on us."