A No-Fly Zone (NFZ) as a concept was introduced in the 1990s.
In an NFZ, a military power prohibits certain aircraft types from entering designated airspace.
This designated airspace could be a region in a country or the whole country.
An NFZ is enforced by the threat of force.
This means deploying surveillance aircraft to monitor the airspace and fighters to shoot down the “prohibited” aircraft.
It also means destroying the enemy’s ground-based anti-aircraft systems that could attack the country’s surveillance or fighter aircraft.
The modern NFZ was first used in the 1990s after Saddam Hussein, Iraq’s then-dictator, attacked Kurds in the north of his country and Shias in the south.
The US, Britain and France alliance had then declared NFZs in these regions.
To enforce it, they flew around 225,000 aircraft between 1991 and 2003 (France pulled out in 1996).
The Ukrainian President had requested the US and NATO to create an NFZ over Ukraine around a month ago.
This would have meant the US/UK attacking Russian planes, potentially leading to a direct military conflict with Russia (a world-war like situation).
