Ponca City, We Love You writes "America's entire B-2 stealth bomber fleet, which has played a crucial part in all major US conflicts since 1989, has been grounded after one of the jets crashed near a military base in Guam. The crash — the first involving the B-2 — was the most expensive single aircraft accident in history. (The planes cost $1.2B each.) Officials assume the crash was caused by either mechanical failure or human error, but have grounded all B-2s to ensure there is not some fundamental fault developing in the 21-strong fleet. The crash occurred Saturday morning local time as the B-2 was taking off from Andersen Air Force base on Guam, a US territory south of Japan. An Air Force spokesman said, 'The cause of crash is unknown, pending an investigation. The pilots had ejected safely — no serious injuries. One is mobile, one is still in the hospital under observation.'"