Boeing and the union representing striking machinists have negotiated a new contract proposal that would provide bigger pay raises and bonuses in a bid to end a costly walkout that has crippled production of airplanes for more than a month.

The International Association of Machinists and Aerospace Workers said early Saturday that it plans to hold a ratification vote on Wednesday.

The union said the Boeing offer would increase pay by 35% over four years, up from 30% that the company offered last month. It also boosts the ratification bonus to $7,000 per worker instead of $6,000.

The new offer would not restore a traditional pension plan — a key demand of the 33,000 striking workers — but it would increase the amount of contributions to 401(k) retirement plans that Boeing would match. It would also retain performance bonuses that Boeing wanted to eliminate and make them at least 4% of pay, the union said. — The Associated Press