No-Fly Zone

Definition

A no-fly zone is an airspace restriction established over a designated area, typically enforced by military power, in which certain aircraft are prohibited from flying. No-fly zones are imposed to protect civilian populations from aerial bombardment, enforce ceasefire agreements, or deny an adversary air superiority. Enforcement requires sustained air patrol, suppression of enemy air defenses (SEAD), and willingness to engage violators — making it a significant military commitment that can escalate into broader conflict. Notable no-fly zones include those over Iraq (1991–2003) and Libya (2011). Establishing a no-fly zone against a state with advanced air defenses is considered a de facto act of war.