During the closing years of World War II, both Japan and the United States came up with unusual ways to get bombs to enemy sites. The United States developed a plan to use bats to carry bombs to Tokyo buildings, and the Japanese actually implemented a balloon bomb offensive on mainland USA. In 1944 and 1945, over a 5 month period, Japan launched over 9000 balloons carrying anti-personnel and incendiary bombs. These balloon bombs (called Fugos) were ingeniously designed to rise into the fast traveling jet-stream, and thus cross the Pacific Ocean in 3 days or so. Using a system of ballasts and blow plugs, the balloons would ideally drop their bombs on North America at random points and create panic and chaos. In reality, only around 300 of these bombs were ever sighted in America, and the only fatalities were 5 children and their Sunday school teacher, who died after dragging one of the bombs from the woods near Lakeview, Oregon. One balloon did land on a power line near Cold Creek, Washington, coincidentally idling the nuclear power plant there that was later used to make plutonium for the Atomic Bomb.
The actual balloons used in the Fugos were of two types. One was rubberized silk, and the other more common balloon was made of mulberry paper. The balloons were about 100' in diameter and held 19,000 cubic feet of hydrogen. The balloons carried two types of bombs, one 15 Kilogram high explosive anti-personnel bomb, and five 5 or 12 Kilogram Theremite (incendiary) bombs. Military officials were worried that the bombs could also be used as a vehicle for germ warfare had the Japanese decided to do so. Supplies of decontamination chemicals and sprays to counter any possible use of germ warfare were quietly distributed in the western states.
The first balloons, launched on November 3, 1944 were sighted two days later southwest of San Pedro, California. To counter the threat, Air Force and Navy fighters flew intercept missions to shoot down balloons when sighted and personnel were stationed at critical points to combat any forest fires which might occur. The government, with the cooperation of the news media, adopted a policy of silence to reduce the chance of panic among U.S. residents and to deny the Japanese any information on the success of the launches. Indeed, the launches of the balloons were ceased after several months, the Japanese apparently discouraged by the apparent failure of the balloons. After the deaths of civilians in Oregon, however, the U.S. Government quickly publicized the balloon bombs, warning people not to tamper with them.