Even if the union ratifies the new contract, Boeing still has to confront a slew of issues with its aircraft programs.

The latest proposal includes a 35% general wage increase over four years — bringing it closer to the union's original ask for 40%. Boeing previously offered a 25% raise over the life of the contract.

Boeing reached a tentative deal Saturday with its unionized machinists to end a strike that has dragged on for more than a month, delaying production and leading to thousands of layoffs, union officials say.