With Every Letter (Wings of the Nightingale #1)
Sarah Sundin

As their letters crisscross the Atlantic, Tom and Mellie develop a unique friendship despite not knowing the other's true identity. When both are transferred to Algeria, the two are poised to meet face-to-face for the first time. Will they overcome their fears and reveal who they are, or will their future be held hostage by their pasts?
Combining a flair for romance with excellent research and attention to detail, Sarah Sundin vividly brings to life the perilous challenges of WWII aviation, nursing--and true love.