So how do countries earn money, quite literally, from thin air?

An air toll:

Are all airspaces as pricey?

How expensive is India?

Why do charges vary?

Is it about the money?

NEW DELHI: While the closure of Pakistan airspace has hit Indian airlines hard , having to re-route flights from India around the neighbouring country, thereby increasing the flying time and cost, it's impacted Pakistan as well, which has lost $100 million (around Rs 688 crore) since February with an average of 400 flights a day skipping the Pakistani airspace.Pakistan closed its airspace after the Indian Air Force 's (IAF's) February 26 Balakot strike . Since then, it has only opened two of 11 air routes and both of them pass through southern Pakistan.On its part, the IAF announced on May 31 that all temporary restrictions imposed on Indian airspace post the Balakot strike have been removed.Airlines pay the civil aviation administration of the country they are flying over a certain fee based on the type of aircraft, the distance covered while overflying a country and the aircraft's all up weight (AUW) or gross weight, which is the weight of an aircraft before it takes off. In Pakistan's case, for a Boeing 737, the charges are $580 through its airspace — which will increase in case an Airbus 380 or Boeing 747 is flying over.No. Canada, for example, charges on the basis of the airplane weight and the distance travelled while its southern neighbour, the US, charges only for the distance. However, the US can afford to be that generous considering its airspace isn’t just restricted to its landmass but extends all the way up to the Philippines — which means that a flight from Japan to New Zealand, which comes nowhere near the continental United States, will still end up paying @$26.51 per 100 nautical miles (roughly 185.2km) to the US FAA.The DGCA sets the overflight and landing charges in India, with domestic flights required pay less than international flights. The charges are calculated by multiplying the distance in nautical miles and the weight with a fixed charge component for airspace fees of Rs 5,330 if the fight lands in India. For those flights which are overflying, the charges are calculated on the basis of the route or the airspace fees, the distance and the weight, with an additional amount of Rs 5,080.Due to closure of airspace by Pakistan, national carrier Air India lost Rs 491 crore till July 2 , according to data presented by civil aviation minister Hardeep Singh Puri in Rajya Sabha. Private airlines SpiceJet, IndiGo and GoAir lost Rs 30.73 crore, Rs 25.1 crore and Rs 2.1 crore, respectively, the data stated.Since 1944, when the US organised an international civil aviation convention in Chicago to try and hammer out an agreement between various countries to remove airspace restrictions for commercial flights — which failed, by the way — all the countries have charged according to their own whims and fancies for 'renting' out their airspace. In fact, air travel has become cheaper since 1990 with the opening up of Chinese and Russian airspaces which were till then off limits to airlines from non-Communist countries, such as the US and western Europe.While money is certainly a consideration in allowing overflight rights — the US, in 2016, by a conservative estimate that assumes just 100 nautical miles of overflying by the various airlines, earned close to $200 million from its airspace while a cash-strapped country such as Pakistan could do a lot with $100 million — there's also politics involved. Flights to and from Israel are not allowed the usage of airspace by the Arab countries while Bahrain, Egypt, Saudi Arabia and UAE have banned overflights by aircraft registered in Qatar due to its alleged support to terrorism. Other countries that have used their airspace as a political tool include China, which denies overflight rights to airlines from Taiwan.