A United States Air Force B-2 Spirit bomber crashes on Guam, marking the first operational loss of a B-2.

The United States Air Force (USAF) is the air service branch of the United States Department of Defense. It is one of the six United States Armed Forces and one of the eight uniformed services of the United States. Tracing its origins to 1 August 1907, as a part of the United States Army Signal Corps, the USAF was established by transfer of personnel from the Army Air Forces with the enactment of the National Security Act of 1947. It is the second youngest branch of the United States Armed Forces and the fourth in order of precedence. The United States Air Force articulates its core missions as air supremacy, global integrated intelligence, surveillance and reconnaissance, rapid global mobility, global strike, and command and control.

The Northrop B-2 Spirit is an American heavy strategic bomber that uses low-observable stealth technology to penetrate sophisticated anti-aircraft defenses. It is often referred to as a stealth bomber.

On 23 February 2008, Spirit of Kansas, a B-2 Spirit stealth bomber of the United States Air Force, crashed on the runway moments after takeoff from Andersen Air Force Base in Guam. The aircraft was destroyed, but both crew members successfully ejected. The accident marked the first operational loss of a B‑2 bomber, and as of 2024 remains one of two lost B-2s since another damaged B-2 had to be retired due to repair costs after an on-board fire. With an estimated loss of US$1.4 billion, considering only the cost of the aircraft, it was also the most expensive aircraft crash in history.