There is conflicting evidence as to whether the Lightwing is a species of dragon or a proper name for an individual dragon, mentioned once in How to Fight a Dragon's Fury.
When the Viking forces charge in to fight the Dragon Rebellion, there is—
|“||Barbara the Barbarian on her Lightwing, her cat balancing in the dragon's head.||”|
|— How to Fight a Dragon's Fury|
This reads, like so many other once-mentioned dragons, as a dragon species name. Lightwing is not mentioned again.
However, an image of the Viking dragons with their riders charging into battle is also provided in How to Fight a Dragon's Fury, seen at right in the InfoBox. Though rather masculine in this depiction, the rider is most likely Barbara the Barbarian. The dragon however, looks like a Rocket Ripper, even by the way the Viking is riding this dragon. Another possibility is this is another member of the Barbarian tribe (they train warrior cats) on a Rocket Ripper. However the hair, cat, and placement of the scratch marks and Dragonmark all match up with an earlier picture of Barbara the Barbarian. Either theory is plausible.
Concerning classification, if the Lightwing is indeed a Rocket Ripper, it would be a Sky Dragon. Should the Lightwing be a separate species, classing it as a Sky Dragon is still entirely plausible, due to its high rapid flying and many Riding Dragons are of the Sky Dragon class.
The Lightwing is mentioned as the Riding dragon of Barbara the Barbarian.