API IsFlyableArea

Checks if the character's current location is classified as being a flyable area. canFly = IsFlyableArea

Returns
true if the area is classified as flyable, false otherwise.

Details

 * As of patch 3.2, this function works properly, returning nil in non-flyable areas of Dalaran and when flying is prohibited in Wintergrasp (during battle I believe).
 * As of patch 3.3, this function returns 1 in Wintergrasp during battle, while you can't really use your flying mount.