Blizzard hasn't made flying available at the beginning of a new expansion set for a long time. In this way, all players are forced to explore new zones and areas by land. However, we already know the requirements that have to be met in order to unlock flying in the Zandalar and Kul Tiras islands, which were introduced in the new Battle for Azeroth expansion.
At the moment we don't have any data that tells which update will unlock flying, but you can already do some preparations so you won't waste any time in the future on meeting the requirements.
Pathfinder, Part One
As in the Legion expansion, the basic requirement in the latest add-on is to achieve Pathfinder, Part One. The two factions have practically identical goals and requirements to unlock increased mount speed:
- The Horde must complete all three major campaigns in Zandalar and complete the story with a Zandalar Forever! achievement. To do this, you need to explore all the locations on all the islands (including Kul Tiras) and gain Revered reputation with each faction available in Battle for Azeroth.
- The Alliance, in turn, has to complete the plot paths for the main campaign in order to achieve Kul Tourist. They also must explore 100% of all the islands in Battle for Azeroth and earn at least Revered reputation status with their factions.
The last two requirements are also common to both sides of the conflict. You need to complete 100 different World Quests and make an additional feature, War Campaign, for your faction. In this way you will unlock the Ready to War achievement.
It is worth mentioning that Pathfinder, Part One is an account wide achievement. This means that once gained, it will be available to all characters, regardless of the server.
Pathfinder, Part Two?
Unlocking The Pathfinder, Part One achievement will also increase your ground mount speed in the lands of Battle for Azeroth. It's worthwhile to put some effort into it. In addition, further requirements are not yet known. As with the Legion, Blizzard will announce the requirements of The Pathfinder, Part Two in the future patch.
It is quite certain that you will have to achieve a second part of the achievement to get flying in Kul Tiras and Zandalar. However, right now the requirements are unknown. Blizzard wants to avoid the situation in which everybody will gain the required achievements earlier and immediately unlock flying. We have to wait further for some new information on this matter.