Bosnian War: NATO forces began Operation Deny Flight (aircraft pictured) to enforce a no-fly zone over Bosnia and Herzegovina ordered by the United Nations Security Council.

The Bosnian War was an international armed conflict that took place in Bosnia and Herzegovina between 1992 and 1995. Following several earlier violent incidents, the war is commonly seen as having started on 6 April 1992 when the newly independent Republic of Bosnia and Herzegovina was internationally recognized. It ended on 21 November 1995 when the Dayton Accords were initialed. The main belligerents were the forces of the government of the Republic of Bosnia and Herzegovina, and those of the breakaway proto-states of the Republic of Herzeg-Bosnia and the Republika Srpska which were led and supplied by Croatia and Serbia, respectively.

The North Atlantic Treaty Organization, also called the North Atlantic Alliance, is an intergovernmental military alliance between 32 member states—30 in Europe and 2 in North America. Founded in the aftermath of World War II, NATO was established with the signing of the North Atlantic Treaty in 1949. The organization serves as a system of collective security, whereby its independent member states agree to mutual defence in response to an attack by any external party. This is enshrined in Article 5 of the treaty, which states that an armed attack against one member shall be considered an attack against them all.

Operation Deny Flight was a North Atlantic Treaty Organization (NATO) operation that began on 12 April 1993 as the enforcement of a United Nations (UN) no-fly zone over Bosnia and Herzegovina. The United Nations and NATO later expanded the mission of the operation to include providing close air support for UN troops in Bosnia and carrying out coercive air strikes against targets in Bosnia. Twelve NATO members contributed forces to the operation and, by its end on 20 December 1995, NATO pilots had flown 100,420 sorties.

A no-fly zone, also known as a no-flight zone (NFZ), or air exclusion zone (AEZ), is a territory or area established by a military power over which certain aircraft are not permitted to fly. Such zones are usually set up in an enemy power's territory during a conflict for humanitarian or military reasons without consent of the enemy state, similar in concept to an aerial demilitarized zone, and usually intend to prohibit the enemy's military aircraft from operating in the region. Military action is employed by the enforcing state and, depending on the terms of the NFZ, may include preemptive attacks to prevent potential violations, reactive force targeted at violating aircraft, or surveillance with no use of force. Air exclusion zones and anti-aircraft defences are sometimes set up in a civilian context, for example to protect sensitive locations, or events such as the 2012 London Olympic Games, against terrorist air attack. A no-fly zone is generally not considered a form of aerial blockade due to its more limited scope compared to an aerial blockade.