If lucky the speeds can be read from the creature when flying... but considering when you mount you can't directly query the creature itself, this will be a bit hard, or maybe it's just a creature ID for the visuals, the speeds may be hardcoded in the exe maybe, since it's a bit unlikely that they are in the DBC, but maybe you are more awesome then me, so I put the files in a zip if you like to peak at the source data.
