Legacy by Tana Stone

The Drexian Academy has four schools and four rules.

Beware of the Assassins.
Don’t cross the Blades.
Trust the Irons.
The Wings go as one.

Break them at your peril.

Ariana is the first human instructor at the Drexian Academy and the first female to teach flight to cocky cadets. She’s the best Earth has to offer with a lot to prove. But it will take more than being the best to survive the secret requirements, unwritten rules, and ancient traditions of the alien military training school.
Volten lacks the one thing Drexians value most—a proud and respected clan. He’s risen to the position of flight instructor at the academy without a lineage to speak of, but not without paying a steep price. One thing he doesn’t count on as he ascends the ranks is the beautiful human pilot who might threaten everything that’s within his grasp.
Within the dark walls of the school lie secrets that could tear both pilots’ worlds apart. Beyond the stone towers and cruel spires are dangers neither could imagine. Will these wings go as one. . . risk it all to break the rules. . . or break each other?