Context

• Pakistan has extended the ban on use of its airspace till June 15.
• A notice to airmen (NOTAM) informed airlines about the extension of the ban.

About

• In the wake of escalating tension following an airstrike by Indian Air Force in Balakot in February 2019, Pakistan had restricted its airspace for airlines to and from India.
• Several Central Asian airlines as well as those providing connectivity to Europe and the United States from Southeast Asia were forced to cancel their flights due to the ban.
• The ban is contributing to financial losses owing to longer routes, demand of passengers on these routes, increased crew presence and increased fuel costs.
• In a case of Air space violation, a Delhi-bound Georgian aircraft that took off from Karachi was recently intercepted over Gujarat.
• However, on the up side, recently, India granted permission for Pakistan Foreign Minister Shah Mehmood Qureshi’s aircraft to fly over the country for his visit to Male and Colombo. Pakistan too exempted External Affairs Minister Sushma Swaraj to fly directly through Pakistani airspace to attend the SCO meet in Bishkek.

Airspace: In international law, the space above a particular nation’s territory is owned by the government controlling the territory.

• The upper limit of national airspace is not defined by international law. However, under the Outer Space Treatyof 1967, airspace ends where outer space begins, as outer space is declared to be free and not subject to national appropriation
• The treaty, however, did not define the altitude at which outer space begins and airspace ends.

Air sovereignty: It is the fundamental right of a sovereign state to regulate the use of its airspace and enforce its own aviation law. State controls the entry of foreign aircraft into its territory and that persons within its territory are subject to its laws

• The principle of airspace sovereignty is established through the Paris Convention on the Regulation of Aerial Navigation (1919) and subsequently by other multilateral treaties.
• Commercial air transport is divided into scheduled air services and nonscheduled flights. Charter flights fall mostly, but not invariably, into the latter category.
• Under the 1994 Chicago Convention, contracting states agree to permit aircraft registered in the other contracting states and engaged in commercial nonscheduled flights to fly into their territory without prior diplomatic permission and, moreover, to pick up and discharge passengers, cargo, and mail, but in practice this provision has become a dead letter.

Prohibited airspace: It refers to an area of airspace within which flight of aircraft is not allowed, usually due to security concerns. It is one of many types of special use airspace designations and is depicted on aeronautical charts with the letter "P" followed by a serial number.

Restricted airspace: Different from prohibited airspace, in it the entry is typically forbidden at all times from all aircraft and is not subject to clearance from ATC or the airspace's controlling body.

How closure of Airspace affects airlines?

• Globally, commercial airlines generally fly from east to west. All airlines seek to fly a straight route so as to save fuel. This is possible only when the airspace over a country, which is the sovereign right of that country, is open and be safe to fly over.

Every country marks out several entry and exit points for various airlines to use. When these entry and exit points are shut, airlines need to consider alternative routes, which involve flying longer or stopping at an intermediate point before reaching their final destinations.