One hundred stealth bombers. That has been the number since the B-21 Raider programme was announced — the minimum buy the Air Force said it needed to replace the aging B-2 Spirit and B-1B Lancer fleets. One hundred was already ambitious. Now the man who controls the Pentagon’s chequebook says it is not enough.

Defense Secretary Pete Hegseth told lawmakers on April 30 that the United States will require “a lot more, over 100” B-21 Raiders — the most explicit signal yet from the top of the Department of Defense that America’s next stealth bomber fleet is about to get significantly larger.

From Floor to Ceiling

The Air Force has always described 100 B-21s as a “minimum” — careful language that left the door open for expansion. But budgets speak louder than adjectives, and until now, the Future Years Defense Program funded exactly 100. Hegseth’s statement, volunteered during testimony rather than extracted under questioning, changes the political dynamics. When the Secretary of Defense says the military needs more of something, Congress tends to listen — especially when the weapon in question is built in California, a state with significant defence-industry employment.

Hegseth is not alone. The last two commanders of U.S. Strategic Command — the unified command responsible for the nation’s nuclear deterrent — have both endorsed increasing the buy to 145 airframes. Admiral Charles Richard, who led STRATCOM until 2022, argued that 100 bombers could not simultaneously meet nuclear deterrence, conventional strike, and ISR requirements across two theatres. His successor continued that argument, and the Pacific commander has added his voice, pointing to the vast distances of the Indo-Pacific as a reason for more airframes.

The Math of 145

Why 145? The logic is straightforward. A fleet of 100 bombers sounds formidable, but military accounting erodes that number quickly. At any given time, roughly 60 percent of a bomber fleet is available for operations — the rest is in depot maintenance, undergoing modifications, or assigned to training. That leaves 60 mission-capable B-21s. Split between nuclear alert, conventional deterrence in the Pacific, and commitments in other theatres, and each combatant commander gets a surprisingly thin slice.

At 145 airframes, the available force rises to roughly 87 mission-capable bombers — enough to maintain a credible nuclear alert posture while still generating the conventional mass needed for a Pacific campaign. The extra 45 aircraft also provide a buffer against combat losses, which even stealth aircraft would suffer in a high-end conflict.

What It Would Cost

The B-21’s unit cost is classified in detail, but the Air Force has confirmed a target of approximately $750 million per aircraft in fiscal year 2022 dollars. Adjusted for inflation and assuming a mature production line, 145 bombers could cost roughly $120 billion over two decades — an enormous sum, but one that represents less than 1 percent of cumulative defence spending over that period.

Northrop Grumman is already scaling up production at Plant 42 in Palmdale, California. The company has invested in new manufacturing facilities, and the Air Force has accelerated the production timeline. The current plan calls for a gradual ramp from low-rate initial production to full-rate production by the late 2020s. Adding 45 more aircraft to the run would extend the production line — good news for Northrop Grumman’s workforce and Southern California’s economy.

The Biggest Stealth Fleet Ever

If Hegseth’s vision materialises, the B-21 fleet would dwarf every stealth bomber force that came before it. The Air Force built only 21 B-2 Spirits — a fleet so small that losing a single aircraft to a hangar fire in 2008 represented nearly 5 percent of the entire force. The B-21 programme was designed from the outset to avoid that mistake: more affordable, more producible, and more numerous.

At 145 aircraft, the Raider fleet would give the United States a long-range stealth strike capability without historical precedent. Whether Congress will write the cheques remains an open question. But with the Defense Secretary, STRATCOM, and PACOM all pushing in the same direction, the 100-bomber floor is looking increasingly like a starting point — not a ceiling.

Sources: Air & Space Forces Magazine, FlightGlobal, 19FortyFive