On June 5, 2017, four Arab countries: Bahrain, Egypt, the United Arab Emirates (UAE), and Saudi Arabia (“the Quartet”), severed their diplomatic and economic relations with Qatar. They adopted a series of restrictive measures relating to terrestrial, maritime and aerial lines of communication against Qatar, including aviation restrictions. Pursuant to this, Qatar-registered aircraft and some non-Qatar-registered aircraft were denied the right to overfly the respective territories of Quartet. All the Qatar-registered flights were barred from landing at or departing from their airports, while prior permission was required for some non-Qatar registered aircraft