The US Air Force (USAF) made a massive show of force during recent drills, launching a sortie of 12 Northrop Grumman B-2 Spirit stealth bombers.

Taking place on 15 April from Whiteman AFB in Missouri, the sortie occurred during Spirit Vigilance, an annual strategic bomber exercise designed to test the readiness of the B-2 fleet.

The display included a so-called “elephant walk” – involving numerous aircraft taxiing in close succession – followed by a “mass fly-off”, according to the USAF.

Air Force Global Strike Command, which oversees the USA’s ground-based ballistic missiles and heavy bombers, has previously described Spirit Vigilance as a display of the service’s ability to “rapidly generate and deploy the B-2 under greater scrutiny and time restraints than the normal day-to-day flying missions”.

The B-2 is the Pentagon’s only nuclear-capable stealth bomber. The USAF maintains a fleet of just 20 of the bombers, owing to the type’s staggering price: $2.2 billion per aircraft in current-value dollars.

B-2s are also notoriously difficult to maintain, often requiring lengthy periods of maintenance to retain their stealthy profile, and requiring full overhauls every nine years. Those maintenance requirements and the small size of the fleet mean the USAF seldom operates sorties composed of so many of the flying-wing bombers.

The 15 April sortie represented 60% of the total B-2 fleet.

Washington hopes to alleviate those constraints with the B-2’s successor – Northrop’s B-21 Raider. The USAF intends to have a much larger B-21 fleet (it has committed to buying at least 100 of the type), and expects Raiders will have much better operational availability. Northrop has said the B-21 is designed to be a “daily flyer”, with reliability and ease of maintenance being key programme goals.

The B-21 is currently in flight testing, with at least one flying prototype in operation and five more examples under production.

Delivery of the first Raider is expected sometime in the mid-2020s, according to the USAF, which intends to station the first operational aircraft at Ellsworth AFB in South Dakota.

Meantime, B-2s remains a key pillar of the USA’s so-called “nuclear triad”, which consists of bombers, ground-based ballistic missiles and submarine-launched ballistic missiles.

Northrop is planning a series of fleet modernisations meant to keep Spirits flying until, potentially, the 2050s. Work is to include application of new low-observable materials intended to reduce the B-2’s maintenance burden.

Washington has placed Spirits on prominent display around the world in the past year, deploying a trio of the bombers to Iceland last August. One of those aircraft then completed a trans-polar flight to Alaska for training in the USA’s far northern territory.

The high-profile flights come after the B-2 fleet was grounded in late 2022 after an undisclosed malfunction mid-flight forced a B-2 crew to execute an emergency landing that damaged the aircraft and the main runway at Whiteman AFB.