Wings of Creation — Brenda Cooper

Joseph has succeeded in rescuing his sister, Chelo, from a pitched battle on the colony planet Fremont. Now he and Chelo and the love of his life, Alicia, and all of their extended family, are finally returning home. Halfway there, a probe intercepts them, sending them new coordinates and a message from Joseph's enigmatic supporter and teacher, Marcus.

War is brewing.

Joseph is wanted for escaping to save Chelo. To stay safe, Joseph must bring his family and friends to the renowned planet of Lopali, where men and women can fly, and peace and freedom abound. Or do they? Alicia has always wanted to fly, but the modifications that give humans wings kill as often as they work.

Joseph must learn to actually change humans, to free the fliers of a tyranny that has enslaved them, since their species was born. If he can do this, the fliers have agreed to help him stop the war. But it's not as easy as it seems.