Military forces have used aircraft to drop leaflets to attempt to alter the behavior of combatants and non-combatants in enemy-controlled territory, sometimes in conjunction with air strikes. Humanitarian air missions, in cooperation with leaflet propaganda, can turn the populace against their leadership while preparing them for the arrival of enemy combatants.
There are six different functions of airborne leaflet propaganda that have been used over the past century:
Airborne leaflets have been used for military propaganda purposes at least since the 19th century. One early example is from the Franco-Prussian War when, in October 1870 during the Siege of Paris, a French balloon coming from the city dropped government proclamations over Prussian troops that stated the following (in German):
Paris defies the enemy. The whole of France rallies. Death to the invaders. Foolish people, shall we always throttle one another for the pleasure and proudness of Kings? Glory and conquest are crimes; defeat brings hate and desire for vengeance. Only one war is just and holy; that of independence.
Aerial leaflets were first used on a large scale during World War I by all parties. The British dropped packets of leaflets over German trenches containing postcards from prisoners of war detailing their humane conditions, surrender notices and general propaganda against the Kaiser and the German generals. By the end of the war MI7b had distributed almost 26 million leaflets.
In August 1918, the famous Italian writer, poet and fighter pilot Gabriele D'Annunzio, organized the Flight over Vienna: a famous propaganda operation during the war, leading 9 Ansaldo SVA planes in a 1,100-kilometre (700 mi) round trip to drop 50,000 propaganda leaflets on the Habsburg capital.
The Germans began shooting the leaflet-dropping pilots, prompting the British to develop an alternative method of delivery. A. Fleming invented the unmanned leaflet balloon in 1917, and these were used extensively in the latter part of the War, with over 48,000 units produced. The hydrogen balloon would drift over no-man's land to land in the enemy trenches.
At least one in seven of these leaflets were not handed in by the soldiers to their superiors, despite severe penalties for that offence. Even General Hindenburg admitted that "Unsuspectingly, many thousands consumed the poison" and POWs admitted to being disillusioned by the propaganda leaflets that depicted the use of German troops as mere cannon fodder. In 1915, the British began airdropping a regular leaflet newspaper Le Courrier de l'Air for civilians in German-occupied France and Belgium.
The first proposal to construct a special bomb with which to disperse airborne leaflets was put forward by British air force officers during World War II. The most successful "leaflet bomb" model of the War was the Monroe bomb, invented in 1943 by USAAF Captain James Monroe of the 305th Bombardment Group. It was developed from laminated paper containers that had been used to transport M-17 incendiary bombs.
The British improved the use of hydrogen balloons to carry leaflets over German lines. Some of the V-1 flying bombs launched by the Germans against southern England carried leaflets - they were contained in a cardboard tube at the tail of a missile. This would be ejected by a small gunpowder charge while the V1 was in mid-air, en route to its target.
Allied airborne leaflets printed during WWII were "factual, in the main truthful, and served (or so it was claimed) to create a reputation for reliability both in supplying information and refuting German accounts which we said to be untruthful". Often the leaflets did not reach their intended targets because they were dropped from such high altitudes and often drifted over lakes and rural areas.
Although leaflets were seen as being an effective tactic in manipulating troops when morale was low, "During the early months of the war, leaflets or pamphlets were scattered over enemy territory by aircraft and balloons but it was more than doubtful whether these had any useful effect, their obvious defects being that few can have reached their targets and, being printed, they were sometimes out of date by the time they were ready to distribute. The front-line distribution of leaflets was quite another matter and these were dropped by aircraft or fired by shells, the messages they bore being less careful about the general principles of consistency and frankness and only truthful about matters on which the enemy had contradictory information". It was found that psychological warfare was not effective when distributing surrender leaflets to an enemy which currently had a high morale amongst its troops. Despite the limitation of airborne leaflets' ineffectiveness on opposing sides with high morale, enemies used this tactic "to cause the men to begin talking to each other about their poor military position, their desire to stay alive for their families' sakes, and the reasonableness of honorable surrender", which often led men to desert their troops.
One example of German leaflets which appealed to American troops was one that depicted a passionate kiss between a man and woman. The leaflet read: "FAREWELL Remember her last kiss ... ? Gee were you happy then ... ! Together, you spent marvelous times ..., lounging on beaches ..., dancing, enjoying parties galore ..., listening to the tunes of your favorite band ...". The leaflet's back side reminds the soldier that his loved one is longing for him and that most of the men he had come with are now dead. In comparison, one Allied leaflet simply showed a picture of a large open field with thousands of German graves.
James A.C. Brown, a Scottish psychiatrist, summed up the WW2 experience with the observation that "Propaganda is successful only when directed at those who are willing to listen, absorb the information, and if possible act on it, and this happens only when the other side is in a condition of lowered morale and is already losing the campaign."
Before the B-29's exclusive deployment to the Pacific Theater began, the USAAF initiated a disinformation campaign through leaflets over the Third Reich early in 1944 that hinted at what sorts of American heavy bombers were likely to appear over Germany in the future. Partly in conjunction with use of YB-29-BW 41-36393, the so-called Hobo Queen, one of the service test aircraft flown around several British airfields in early 1944, four-page German language Sternenbanner-headlined, American-published propaganda leaflets mentioning a "battle of annihilation against the Luftwaffe" (Vernichtungsschlacht gegen die Luftwaffe), dated to Leap Year Day in 1944, were dropped over the Reich, with the intent to deceive the Germans into believing that the B-29 would be deployed to Europe.
Leaflets were also used by the USAAF on Japan during the Pacific War. In mid-1945 it became apparent that B-29 bombers of the USAAF were raiding Japan's cities without meeting significant resistance. General Curtis LeMay, commander of the XXI Bomber Command, part of the Twentieth Air Force, consequently ordered the dropping of leaflets hoping to reduce the needless killing of innocent people. One of the leaflets dropped on targeted Japan's cities, with the text on the back, read:
Read this carefully as it may save your life or the life of a relative or a friend. In the next few days, some or all of the cities named on the reverse side will be destroyed by American bombs. These cities contain military installations and workshops or factories, which produce military goods. We are determined to destroy all of the tools of the military clique that they are using to prolong this useless war. Unfortunately, bombs have no eyes. So, in accordance with America's well-known humanitarian policies, the American Air Force, which does not wish to injure innocent people, now gives you warning to evacuate the cities named and save your lives.
America is not fighting the Japanese people but is fighting the military clique, which has enslaved the Japanese people. The peace, which America will bring, will free the people from the oppression of the Japanese military clique and mean the emergence of a new and better Japan.
You can restore peace by demanding new and better leaders who will end the War.
We cannot promise that only these cities will be among those attacked, but some or all of them will be, so heed this warning and evacuate these cities immediately.
It has been estimated that B-29s dropped 10 million propaganda leaflets in May, 20 million in June and 30 million in July. The Japanese government implemented harsh penalties against civilians who kept copies of these leaflets.
Even though leaflet propaganda has been an effective "weapon", its use has been on a decline. This decline is a result of the advance of satellite, television, and radio technology. Six billion leaflets were dropped in Western Europe and 40 million leaflets dropped by the United States Army Air Forces over Japan in 1945 during World War II. One billion were used during the Korean War while only 31 million have been used in the war against Iraq. Other conflicts where leaflet propaganda has been used are Vietnam, Afghanistan (both during the Soviet and more recent NATO invasions), and the Gulf War. Coalition forces dropped pamphlets encouraging Iraqi troops not to fight during the first Gulf War, which contributed to eighty-seven thousand Iraqi troops surrendering in 1991. Leaflet propaganda was also used in Syria to deter possible ISIS recruits from joining in 2015.
Releasing the leaflets can be as simple as having one or more of the aircraft's crew throw bundles of paper from an open hatchway.
A more sophisticated method is the leaflet bomb: a bomb-shaped but non-explosive container that drops from the aircraft and opens in mid-air to disperse leaflets - up to tens of thousands of leaflets per "bomb". U.S. leaflet bombs include the PDU-5B dispenser unit, the LBU30 and the older M129E1/E2. The M129 weighs 52 kilograms (115 lb) when empty and about 100 kilograms (220 lb) loaded. It can contain 60,000 to 80,000 leaflets. At a pre-determined time after release, the two halves of the bomb's outer shell are blown apart by detonating cord, dispersing the leaflet payload. Soviet/Russian leaflet bombs include the AGITAB-250-85 and the AGITAB-500-300 (used during the First Chechen War).
Leaflet bombs have not only been used by states for purposes of military warfare but have, since the 1940s, also been used by radical political and ideological sub-state groups.
The use of leaflet bombs by non-state groups began in 1945 when the Irgun group developed a bomb that was "deposited in the street, ticked away until detonation, then scattered news sheet over a wide and smoky area". In September 1945 three of Irgun's leaflet bombs exploded in Jerusalem and injured nine people.
In the late 1960s the African National Congress (ANC) started to use a version of the leaflet bomb in South Africa. This bomb was developed in collaboration with the South African Communist Party (SACP) and South Africans living in exile in London. The first time this leaflet bomb, known to South African activists as the "bucket bomb" and to the South African police forces as the "ideological bomb", was used was in 1967. This was one of the most important propaganda weapons of the ANC who devoted major resources to it and used it frequently during the 1960s and 1970s, spreading tens of thousands of leaflets. A 1970 article from the ANC's journal Sechaba, looking back at the uses of leaflets as propaganda in the 1960s, stated:
It was in this new period that underground propaganda, demonstrating the effectiveness of the ANC machinery and projecting its voice, became of incalculable value. Underground leaflets began to appear in the townships, factories and city streets. Passed on from hand to hand, these reminded the people that the spirit of resistance must never die. These were often complemented by slogans painted on walls proclaiming: "Free Mandela", "Free Sisulu" and "Long Live the ANC". As modest as these propaganda efforts were ... they showed that the ANC could survive the most severe measures of the regime.
The South African press and security forces also saw it as a serious weapon of the ANC and there were threats from the police to take action against the South African press for publishing parts of ANC's leaflets. The South African Minister of Police was quoted in a South African newspaper thus: "the explosions are an indication that subversive elements are still active" inside South Africa and warned the public that they "must not think the dangers are a thing of the past. It is something with which we will just have to live."
The leaflet bomb has been relatively popular in Latin America with several recorded uses by various groups advocating political violence.
In the 1980s the FMLN in El Salvador used this technology under the name of "propaganda bomb". It was one of the "favorite tactics" of its urban militia groups and preferably used in public places like markets or public parks. The design of the bomb was adapted to the local environment in that it
consisted of a cardboard box with a small, low-power explosive underneath a large number of propaganda leaflets. The explosive was set off by a homemade time igniter. The box was disguised to look like any ordinary package or box that might be carried by someone going or returning from a trip to the marketplace.
The use of leaflet bombs played a part in the FMLN's recruitment process known to them as fogueo - which meant to experience fire or fire-harden something - which was the process by which the recruits "were toughened and the weak and fainthearted were weeded out". The fogueo process was
a very carefully designed program of increasingly risky operations in support of the guerilla movement. As the candidates successfully completed each operation, it gave them confidence to carry out the next danger level of operation until they became full-fledged guerilla combatants.
This process began with low-level information-gathering and propaganda activities in support of FMLN where the culminating activity before being ready for "combat military activity" could be the making and exploding of a leaflet bomb.
In Ecuador several groups have used leaflet bombs. The Revolutionary Armed Corps (CAR) was according to the Ecuadorian police "an extreme leftist group" which is only known for one attempted attack on February 20, 2001, when a leaflet bomb containing 150 pamphlets was discovered and successfully defused by the police.
The communist Group of Popular Combatants (GCP) has used leaflet bombs on several occasions during 2001-2005. In 2001 it was blamed by authorities for a pamphlet bomb and later the same year the group claimed responsibility for detonating a pamphlet bomb in downtown Quito that let out hundreds of pamphlets protesting against Plan Colombia. In 2002 the Revolutionary Armed Forces of Ecuador set off a leaflet bomb in a McDonald's restaurant in Guayaquil that injured three people and caused severe damage to the property.