By Scott Hamilton

Jan. 20, 2026, © Leeham News: Boeing is preparing to activate its North Line for 737 production by mid-year, with 737-8s and 737-9s first to be assembled as a prelude to its intended purpose: assembling the long-delayed 737-10.

Boeing has been informally asking the Federal Aviation Administration (FAA) a series of “what if” questions in advance of a formal request to activate the North Line. This is the first time the 737 will be assembled away from its Renton (WA) facility, which has served as its home since the original model program more than 50 years ago.

This is important because the North Line is brand new, it needs FAA certification, and the MAX 10 is new (only a couple have been built at Renton), pending certification. Employees who will be assigned to the North Line will be a mix of Renton transfers, new hires, and Everett incumbents. The latter has never built a 737.

Boeing 787 bay at the Everett factory in 2023. Boeing was engaged in reworking following discovery of a production flaw. Credit: Leeham News.

Gaining FAA approval to build the 737-8/9 on the North Line will smooth production certification and enable employees without 737 production experience to gain some before the MAX 10 is added to the line. While Boeing all along said the North Line is intended for the MAX 10, LNA confirmed that it is capable of assembling the MAX 8, 9, and 10.

Additionally, since the MAX 10 (and the smallest family member, the MAX 7) remain uncertified pending changes that must be made as a result of the overall 737 MAX crisis revelations, Boeing wants to avoid building up an inventory of MAX 10s that would require changes mandated by the FAA.

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The company wants to begin production as early as May or June. Earlier, Boeing previously said activating the line may not occur until the end of the year, awaiting certification of the 737-10. More recently, CEO Kelly Ortberg identified mid-year as the activation target date. A formal request to the FAA may come as early as March.

Ahead of its year-end 2025 earnings call and in its quiet period, Boeing declined to comment.

Shifting Employees

Officials want to reassign 737 workers from the Renton area to the Everett widebody production plant, where the North Line is located. Under terms of the labor contracts, the IAM 751 follows a seniority list in the assignment of personnel between Renton and Everett. These members assemble the airplanes. The engineers and technicians SPEEA contract does not require pre-approval for moving people around.

LNA is told that Boeing officials want a few more months of smooth operations at a production rate of 42/mo before seeking FAA approval to activate the North Line. The FAA also must approve Boeing’s plans to boost the production rate to 47/mo this year, perhaps in the second quarter. A rate boost to 52/mo by year end requires an up-and-running North Line. If certification of the MAX 10 slips from late 2026 into 2027, the North Line will soon be ready for the rate break to 52/mo with or without the MAX 10.

Production at the Renton plant will be capped at 47/mo, said program GM Katie Ringgold during a recent media tour of the plant. Before the first of several safety crises erupted at Boeing, beginning with the March 10, 2019, crash of an Ethiopian Airlines 737-8 MAX, Boeing produced 52 airplanes a month at the Renton factory. Boeing was preparing to boost the rate to 57/mo; the plant had the capacity to produce 63/mo.

However, given the safety and quality control shortcomings that emerged following that Ethiopian crash, and again after the Jan. 5, 2024, door plug blow-out on a new 737-9 operated by Alaska Airlines, total production of the Renton plant will be capped at 47/mo. This is an average of 15.6 aircraft per month on each of the three lines.

One North Line or Two?

The North Line has been established in the old 787 final assembly bay in Everett. Boeing hasn’t announced what the capacity of this line will be, but LNA reported last June that a Boeing employee predicted that eventually 15 737s would be seen in that bay in 2026. (This timing now appears to be ambitious.) LNA also reported then that production at the Renton factory would likely be capped at 47/mo.

Assuming the North Line will have the same capacity as those in Renton—15.6/mo—this gives Boeing the ability to produce 63 737s a month. Although Boeing now has a backlog of more than 1,300 MAX 10s, the North Line’s ability to produce the MAX 8 and 9 gives Boeing additional flexibility—and room is in the bay to add a second assembly line.

At the end of 2025, Boeing’s 737 delivery stream shows the program is sold out at a rate of 52 next year, in 2028 and beyond at a rate of 57, and potentially in 2029 even at rate 63. Boeing already announced two big orders last month from Aviation Capital Group (50) and Alaska Air Group (105) for 737-8s and 737-10s. Delivery years were not announced. With 2025 orders and options, if all options were exercised, Boeing would need a production rate of about 71/mo in 2030.

If Boeing wants to boost production above 63/mo, a second North Line will be required. The current North Line has been positioned to one side of the old 787 bay. There is room for a second parallel line, according to a former line worker consulted by LNA. Internally, Boeing is looking at this possibility, LNA is told. However, this currently falls into the “what if” thinking, exploring options.