Patch Available - KMST 1.2.481

Probably not. The flying mounts must be coded to apply to the skill, and those that do is from JMS.

In JMS those mounts can fly.
I think it's because they had some event(?) that allowed people to get them who were not 200/120, in the form of skills instead of monster-riding mounts.

Edit:

There was a special NPC, the NPC that hands out the Cash Shop riding skill ticket things in JMS, that had the option to give out skill versions of job-specific mounts in exchange for the actual mount item you bought/did quests for. It's no longer doable, though, since they removed that option a long time ago. Anyone who didn't take advantage of it at that point in time cannot fly without a cash shop mount.