Invasion of airspace by foreign aircraft

Aerial surveillance by foreign powers
Over-flying by foreign aircraft
Independent international air surveillance

Nature

The air space above countries is theoretically controlled by that country, but not in all instances or above certain heights.

Background

In hopes of forging trust between superpower nations, US President Dwight Eisenhower promoted the notion of "open skies" for foreign aircraft in 1955. Cold War suspicions nullified Eisenhower's attempts until 1989, when US President George Bush attempted an open skies revival.

Counter-claim

Over-flying by reconnaissance aircraft builds confidence by allowing each side in a dispute to check that the other is honouring its treaty obligations, especially in relation to military activity.