Lost Bomb Nuclear

 
In 1958, a Mark-15 warhead, packing about 2 Megatons, was jettisoned by a B-47 Bomber when it collided with an F-86 fighter plane

At first, the Air Force claimed there was no nuclear core. However, in 1966, Assistant Secretary of Defense W.J. Howard testified to Congress that it was, indeed, a complete nuclear weapon.
Sweet dreams.