Replacement for the IsFlyableArea API function.

Avoids these long-standing bugs with IsFlyableArea:

Broken Isles zones are only flyable with the Broken Isles Pathfinder ability.
Draenor zones are only flyable with the Draenor Pathfinder ability.
Warlords garrisons and Legion class halls are never flyable.
Ashran and the Tanaan Jungle Intro are never flyable.

Also avoids the new bugs introduced in Patch 7.3.5:

Pandaria zones no longer require Wisdom of the Four Winds.
Northrend zones no longer require Cold Weather Flying.
Eastern Kingdoms, Kalimdor, and Deepholm no longer require Flight Master's License.

These spells were removed from the game, and all characters can fly in these zones, but IsFlyableArea returns false for characters who had not previously learned the appropriate spell.

Usage

lib = LibStub("LibFlyable")
isFlyable = lib:IsFlyableArea() -- true/false

Source code and bug reports on GitHub:
https://github.com/phanx-wow/LibFlyable

URL to use with the CurseForge packager:
https://repos.curseforge.com/wow/libflyable
Only tagged releases are pushed to CurseForge, so using this URL will ensure the packager always gives you a tested and stable version of the library.