U.S. Air Force breaks ground on new B-21 assembly line

The U.S. Air Force and Northrop Grumman have broken ground on a new final assembly line for the B-21 Raider stealth bomber, adding more than 93,000 square meters (1 million square feet) of facilities at Air Force Plant 42 in Palmdale, California.

The construction is tied to the agreement the Department of the Air Force and Northrop reached in February to raise annual B-21 production capacity by 25 percent. Neither the service nor the company disclosed the cost of the new facilities, a completion date, or how many bombers the expanded line will produce each year.

“It’s more than construction… we’re moving fast to build B-21s!” the Office of the Secretary of the Air Force posted on X.

“The B-21 isn’t the only thing taking off,” Northrop Grumman wrote, adding that more than 1 million square feet at Plant 42 is now dedicated to building the bomber.

Northrop builds the Raider at Plant 42 in the same Palmdale complex where it assembled the B-2 Spirit in the 1980s and 1990s, and the first B-21 was unveiled there in December 2022.

The U.S. Air Force is financing the faster schedule with $4.5 billion from fiscal 2025 reconciliation legislation. Northrop CEO Kathy Warden said in April that the company will add $2.5 billion of its own money, including about $200 million in 2026. Northrop says it has already invested more than $5 billion in digital engineering and manufacturing infrastructure for the program.

The production rate is classified, and low-rate initial production has been understood to cover 21 aircraft across five lots. The U.S. Air Force has set a requirement of at least 100 Raiders, with a unit cost reported at around $700 million. In 2025, Northrop took a $477 million charge on the program connected to a production process change for a higher rate.

Northrop has also expanded B-21 work outside California, opening a new manufacturing building called East Gate 3 in Layton, Utah, on September 9. The program draws on more than 400 suppliers in at least 40 states, with final assembly remaining at Plant 42.

In 2025, an Air Force spokesperson told Air & Space Forces Magazine that the planned production increase would be carried out within Northrop’s Palmdale campus and at some major supplier sites. The new assembly line now adds more than 1 million square feet of construction on that campus.

The B-21 is designed to penetrate modern air defenses and strike heavily defended targets with conventional or nuclear weapons. It is set to replace the B-1B Lancer and the B-2, and its design allows for both crewed and uncrewed missions.

The first B-21 flew on November 10, 2023, from Palmdale to Edwards Air Force Base, California, and a second test aircraft joined flight testing at Edwards on September 11, 2025. Low-rate initial production was approved in late 2023 and made public in January 2024.

Ellsworth Air Force Base in South Dakota will be the bomber’s first operational base and training site, and Northrop and the U.S. Air Force say the first aircraft is on track to arrive there in 2027. Air Force Global Strike Command will decide when the B-21 reaches initial operational capability.