We Rule the Night by Bartlett, Claire Eliza

Seventeen-year-old Revna is a factory worker, manufacturing war machines for the Union of the North. When she's caught using illegal magic, she fears being branded a traitor and imprisoned. Meanwhile, on the front lines, Linné defied her father, a Union general, and disguised herself as a boy to join the army. They're both offered a reprieve from punishment if they use their magic in a special women's military flight unit and undertake terrifying, deadly missions under cover of darkness. Revna and Linné can hardly stand to be in the same cockpit, but if they can't fly together, and if they can't find a way to fly well, the enemy's superior firepower will destroy them -- if they don't destroy each other first.

We Rule the Night is a fiercely compelling story about sacrifice, complicated friendships, and survival against impossible odds.