The 13th Warrior

From publisher blurb: The British XIII Squadron was formed in 1915 and transferred to France later that same year. Its emblem is a cat’s head with a sword behind it, so some jokingly call it the “Stabbed Cats” squadron. Others call it the “Unlucky Thirteenth,” though at this time it’s brand new and hasn’t proven lucky or otherwise. In this airborne tale of terror, the heroes are airmen of the British XIII Squadron. Their upcoming trials will pit them against German pilots, social rivals, dark sorcery, and a titanic hunter beyond their wildest nightmares.