CNN's July 15, 2022 Saudi Arabia opens airspace to Israeli flights begins
Saudi Arabia on Friday opened its airspace to all civilian carriers, including all flights to and from Israel, in a step toward normalizing relations between the two nations as US President Joe Biden tours the Middle East.
In a statement shared hours before he was due to fly directly from Israel to Saudi Arabia, Biden hailed the kingdom's decision, saying that it could "help build momentum toward Israel's further integration into the region."
and later
The move fully overturns the decades-long ban on Israeli overflights in Saudi airspace. Israeli airlines flying to Asian routes like India and China previously had to take a detour around Saudi Arabia that added hours to the journey.
Saudi's General Authority of Civil Aviation (GACA) on Thursday said in a statement that it had decided to open its airspace for all air carriers "that meet the requirements of the Authority for overflying." It added that the country is keen "to fulfill its obligations under the Chicago Convention of 1944, which stipulates non-discrimination between civil aircrafts used in international air navigation."
Presumably not much will happen in the air immediately, but economic pressure on "Israeli airlines flying to Asian routes like India and China" makes recovering those added "hours to the journey" attractive.
From a practical standpoint what happens when an airline considers making significant changes to the routes of some of their flights that include overflights they were previously not allowed? Do they calculate and evaluate some alternatives, choose two or three they like then propose them to some regulatory body and to the new country they will overfly and try to get a consensus? Are there historical models of this sort of thing that serve as instructive examples?
Question: What happens procedurally when a country's airlines are now allowed to fly through another country's airspace for the first time? How are the new flight routes selected and agreed upon?