Boeing YB-40 Flying Fortress March 1944. All of the aircraft were sent to reclamation, mostly at RFC Ontario in May 1945, being broken up and smelted. (A couple of the YB-40s can be seen in the 1946 movie "The Best Years of Our Lives", in the famous scene shot at the Ontario "graveyard".) No airframes were sold on the civil market. Boeing YB-40 Flying Fortress The Boeing YB-40 Flying Fortress was a modification for operational testing purposes of the B-17 Flying Fortress bomber aircraft, converted to act as a heavily armed gunship for other bombers during World War II. At the time of its
American Theater (World War II) other heavy bomber projects were cancelled. During the final months of World War II, Japan had planned to use plague as a biological weapon against U.S. civilians in San Diego, California, during Operation Cherry Blossoms at Night. The plan was set to launch at night on September 22, 1945. However it was shelved after Yoshijiro Umezu, Chief of the Imperial Japanese Army General Staff, rejected it. Additionally Japan surrendered five weeks before the plan had been intended to take place. These false alarms have generally been attributed to military and civilian inexperience with war and poor radars of the era.