Aircraft hijacking (also known as Skyjacking) is the take-over of an aircraft, by a (usually) armed person or group. Unlike the hijacking of land vehicles, it is usually not perpetrated in order to rob the cargo. Rather, most aircraft hijackings are committed to use the passengers as hostages and to obtain transport to a location. In the September 11 Terrorist Attack, 2001, the use of hijacked planes as suicide missiles changed the way hijacking was perceived as a security threat.

One task of airport security is to prevent hijacks by screening passengers and keeping weapons off aircraft.

Hijackings for hostages have usually followed a pattern of negotiations between the hijackers and the authorities, followed by some form of settlement -- not always the meeting of the hijackers' original demands -- or the storming of the aircraft by armed police or special forces to rescue the hostages. Previous to September, 2001, the policy of most airlines was for the pilot to comply with hijackers' demands in the hope of a peaceful outcome. Since then, policies have reversed course, in favor of arming and armoring the cockpit.

The first recorded aircraft hijack was on February 21, 1931, in Arequipa, Peru. Byron Rickards flying a Ford Tri-motor was approached on the ground by armed revolutionaries. He refused to fly them anywhere and after a ten day stand-off Rickards was informed that the revolution was successful and he could go in return for giving one of their number a lift to Lima. Most hijackings have not been so farcical. The first hijack of a commercial airliner probably happened on July 16, 1948, when a failed attempt to gain control of a Cathay Pacific seaplane caused it to crash into the sea off Macao.

Since 1947, 60% of hijackings have been refugee escapes. In 1968-69 there was a massive rise in the number of hijacking. In 1968 there were 27 hijackings and attempted hijackings to Cuba. In 1969 there were 82 recorded hijack attempts worldwide, more than twice the total attempts for the whole period 1947-67. Most were Palestinians using hijacks as a political weapon to publicise their cause and to force the Israeli government to releasing Palestinian prisoners from jail.

Airliner hijackings have declined since the peak of 385 incidents between 1967-76. In 1977-86 the total had dropped to 300 incidents and in 1987-96 this figure was reduced to 212.

Other significant hijackings include:

1958 First Cuba to U.S. hijacking
1960 The first US to Cuba hijacking
1968: The first Arab-Israeli hijacking, as three members of Popular Front for the Liberation of Palestine (PFLP) hijack an El Al plane to Rome. Diverting to Algiers the negotiations extend over forty days. Both the hijackers and the hostages go free. This was the first and the only successful hijacking of an El Al flight.
1970: PFLP gunmen attempt to hijack four aircraft simultaneously. They succeed on three and force the planes to fly to the Jordanian desert, where the hijackers blow up the aircraft after releasing most of the hostages. The final hostages are freed in exchange for seven Palestinian prisoners.
1976: The Palestinian hijack of Air France Flight 193 airliner is brought to an end at Entebbe Airport, Uganda by Operation Entebbe: Israeli commandos assault the building holding the hijackers and hostages; they kill all the Palestinian hijackers and free 105 mostly Israeli hostages; three passengers and one commando are killed.
1977: A Palestinian hijack of a Lufthansa airliner Landshut during its flight from Palma de Mallorca to Frankfurt is ended in Mogadishu when German commandos storm the plane. Three hijackers are killed and 86 hostages are freed. The hand of German Red Army Faction is suspected. The pilot is killed.
1978: Two Arab guerrillas seized a plane in Cyprus. Egyptian commandos flew in uninvited to try to take the plane. Cypriot troops resisted and 15 Egyptians died in a 45-minute battle.
1981: A Pakistan International Airlines jet is hijacked and taken to Kabul, where one passenger is killed before the plane flies on to Damascus; the hostages are finally released after 13 days when the Pakistani Government agrees to free fifty political prisoners.
1982: Palestinians take a EgyptAir plane and fly it to Malta. 59 people die when Egyptian commandos storm the aircraft.
1984: Lebanese Shi'a gunmen hijack a Kuwait Airways flight to Tehran. The plane is taken by Iranian security forces.
1985: Lebanese Shi'a gunmen divert a TWA flight from Athens to Beirut with 153 people on board. The stand-off ends after Israel frees 31 Lebanese prisoners.
1986: 22 people are killed when Pakistani security forces storm a Pan Am flight at Karachi, carrying 400 passengers and crew after a 16-hour siege.
1990: Hijackers seize a plane from the People's Republic of China which later crashes as it tried to land in Canton killing 128 people.
1994: Four Islamic GIA terrorists seize Air France Flight 8969 plane in Algiers. It is flown to Marseilles where French commandos storm the plane, killing the hijackers. 170 passengers survive.
1996: Ethiopian Airlines Flight 961 crashed into the Indian Ocean near a beach in the Comoros Islands after hijackers refused to allow the pilot to land and refuel the plane. 125 passengers die and 50 survive. This is only the third incident in which there were survivors of a passenger jet intentionally ditching into water.
1999: All Nippon Airways Flight 61 is hijacked by a lone man. He kills the pilot before he is subdued.
1999-2000: Kashmiri militants hijack Indian Airlines Flight 814 and divert it to Kandahar. After a week-long stand-off India agrees to release three jailed Kashmiri militants in exchange for the hostages. 1 hostage stabbed dead and his body thrown on the tarmac as a "warning attack"
2001: September 11 Terrorist Attack, eastern USA: 19 terrorists hijack four planes (American Airlines Flight 11, American Airlines Flight 77, United Airlines Flight 93, and United Airlines Flight 175; in three cases the aircraft is used as a cruise missile in a suicide bombing of a building; they are the three most deadly of all aircraft hijackings; in the fourth case the intention is the same but the passengers, learning of the fate of the other three planes, attack the cockpit, and the hijackers crash the plane. 'Only' the people in the plane are killed. Altogether, about 3,000 people are killed.

See also airport security