Union membership had previously rejected an offer that included a 30% salary bonus, saying it was not enough to cover cost-of-living increases.
The union was seeking a 40% salary bump and the reinstatement of a defined-benefits pension, which guarantees an income in retirement.
Although the latest offer is closer to the desired salary increase than the previous offer, it does not include a defined-benefits pension, which would guarantee specific monthly benefits upon retirement.
It does include a $7,000 (£5,365) bonus if they accept the deal, reinstated incentive plan and enhanced contributions to workers’ retirement plans, including a one-time $5,000 contribution plus up to 12% in employer contributions, International Association of Machinists and Aerospace Workers Local 751 said.
The strike has dismayed the Biden administration.
Acting US Labour Secretary Julie Su met union representatives and Boeing executives in Seattle this week to encourage a resolution. The company plays an important role in the US economy.
It has also been under scrutiny since an incident in January when a defect caused a panel to blow out on a new Alaska Airlines Boeing 737-MAX jet shortly after takeoff.
The Federal Aviation Administration has barred the planemaker from increasing production, and the agency opened a new safety inquiry into Boeing on Friday.
In July, Boeing agreed to plead guilty to a criminal fraud conspiracy charge and to pay at least $243.6m (£187m) after breaching a 2021 deferred prosecution agreement, in relation to two 737-MAX planes that were lost in nearly-identical accidents that cost 346 lives over five years ago.