Hijackings of passenger aircraft have come to the fore in recent decades with the growth of air travel.
Hijackers normally take over aircraft with the intention of using their passengers as bargaining chips to advance their interests.
Unlike September's terror attacks on the United States, when airliners were taken over for use as guided missiles against prestige buildings, plane hijack situations normally follow a pattern.
At some point, negotiations between the hijackers and the authorities can be expected to begin, followed by a settlement - under which the hijackers' demands may or may not be met - or the storming of the aircraft by special forces.
Special forces are often used to storm hijacked aircraft
Hijackers are sometimes members of organisations that are waging guerilla campaigns against particular countries or governments, and are seeking to gain publicity for their cause. Often, their demands involve the release of fellow members of their organisation who have been imprisoned.
But other, less organised groups have also taken over aircraft - sometimes in a desperate attempt to escape the authoritarian regimes of their homelands.
The longest hijacking incident happened in 1968, when passengers from an El Al plane were held for 40 days after Palestinian militants forced a flight from Rome to divert to Algiers. The Algerian authorities held 22 hostages, releasing the final 12 only after a boycott by international pilots.
Other hijackings in recent decades include:
- 1970: Palestinian gunmen force three planes with a total of 400 people on board to fly to the Jordanian desert, where the hijackers blow up the aircraft - from the United Kingdom, United States and Switzerland - after releasing most of the hostages; after 24 days of talks, the final hostages are freed in exchange for seven Palestinian prisoners
- 1976: The week-long hijack of an Air France airliner in 1976 is brought to an abrupt end at Entebbe Airport, Uganda, by Israeli commandos; they kill all the Palestinian hijackers and free 105 mostly Israeli hostages, but three passengers and one commando die in the raid
- 1977: German commandos storm a Lufthansa airliner in Mogadishu, Somalia, after a five-day stand-off during which Palestinian guerrillas have killed the plane's pilot; three hijackers die in the raid, while 86 hostages are freed
- 1981: A Pakistan International Airlines jet is hijacked and taken to the Afghan capital, 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 more than 50 political prisoners
- 1984: Two American passengers are killed after Shi'a gunmen divert a Kuwait Airways flight to Tehran; the stand-off ends after six days when Iranian security forces disguised as cleaners storm the plane
- 1985: One American is killed and 39 are held for 17 days when 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 mostly Shi'a Lebanese prisoners
- 1985: Fifty-nine people die when Egyptian commandos storm an EgyptAir plane seized by Palestinians and flown to Malta
- 1986: Twenty-two people die when Pakistani security forces storm a Pan Am flight carrying 400 passengers and crew after a 16-hour siege
- 1988: Two Kuwaitis are killed in 1988 when Shi'a gunmen hijack a Kuwait Airways flight from Thailand and force it to fly to Algiers with more than 110 people on board; the hijack ends after 16 days when the hijackers free the remaining hostages and are allowed to leave Algiers
- 1991: Singaporean commandos shoot dead all four hijackers who seized a Singapore Airlines flight
- 1993: Two hijackers and a woman passenger die when security forces storm a hijacked Ethiopian Airlines plane in eastern Ethiopia
- 1998: Pakistani commandos overpower and arrest three hijackers of a Pakistan International Airlines plane at Hyderabad airport; all 29 hostages are freed
- 1999: Kashmiri militants hijack an Indian Airlines aircraft and force it to divert to Kandahar in Afghanistan; one passenger is killed and a week-long stand-off ensues before India agrees to release three jailed Kashmiri militants in exchange for the safe release of the remaining hostages
- February 2000: Afghans seeking to escape the Taleban regime hijack an internal Ariana flight with 164 people on board and force it to divert to Stansted airport near London; a three-day stand-off takes place before the hijackers give themselves up without harming any of the hostages
- October 2000: Two Saudis seeking to highlight alleged human rights abuses in their country divert a Saudi Arabian Airlines plane to Baghdad before surrendering to the Iraqi authorities
- March 2001: Saudi Arabian security forces storm a Vnukovo Airlines plane at Medina airport after it is taken over by Chechen separatists during a flight from Istanbul to Moscow; more than 100 passengers and crew are freed, but three people - one of the hijackers, a Russian air stewardess and a Turkish passenger - are killed